Australian cockroach species

Seeing a cockroach in your home or workplace is rarely a one-off event. Where there is one, there are usually many more hiding close by; the species you are dealing with matters more than most people realise. Australia has around 450 known cockroach species, but only a small number regularly move indoors and become a problem for households and businesses. Identifying the species correctly from the start helps avoid wasted effort and speeds up the process of getting the situation under control.

What are the most common cockroach species in Australia? 

The three main types of cockroaches found in Australian homes and businesses are the German, Australian, and American cockroaches. Other common species include the Oriental, Brown Banded, and Smoky Brown cockroaches, each with unique nesting habits and physical traits.

Identifying the specific cockroach species will help manage an infestation more effectively. See below for descriptions of the appearance, lifestyle, and habits of the cockroaches common in Australia.

• German cockroach (Blatella germanica)
• Oriental cockroach (Blatta orientalis)
• American cockroach (Periplaneta americana)
• Brown banded cockroach (Supella longipalpa)
• Australian cockroach (Periplaneta australasiae)
• Smoky brown cockroach (Periplaneta fuliginosa)

Australian Cockroach

(Periplaneta australasiae)

The Australian cockroach is a mid sized species, growing between 23 and 35mm in length. It is brown in colour with a distinctive yellow margin running along the edges of its forewings and a pale yellow border around the pronotum, which is the shield shaped area behind the head. Despite its name, it is not native to Australia.

Where does the Australian cockroach live?

This species prefers warm, humid outdoor environments and is commonly found around garden beds, leaf litter, mulch, and timber piles. It moves indoors at night, typically entering through gaps around pipes, under doors, or via roof voids. It is more prevalent in areas with mild winters, making it a frequent sighting across Queensland, New South Wales, and Western Australia.

Lifecycle

• Females deposit the ootheca (egg case) containing 24 eggs a day after production.
• After hatching nymphs take 6-12 months to develop into adults.

Habits

• Enter buildings at night from gardens/debris.
• Generally prevalent in areas where winters are relatively mild.
• Despite its name, it isn’t a native species.

Health risks

Like other cockroach species, the Australian cockroach can transfer bacteria including Salmonella and E. coli to food and surfaces it crosses. Its droppings and shed skin can also trigger allergic reactions and aggravate asthma, particularly in children.

German Cockroach

(Blatella germanica)

The German cockroach is one of the most frequently reported pest species in Australian homes and food businesses. Adults grow to around 12 to 15mm in length and are light brown in colour with two dark parallel stripes running along the pronotum. Despite its name, it is found across the world and is notorious for its wide distribution.

Where does the German cockroach live?

The German cockroach prefers warm, humid indoor environments and is most commonly found in kitchens, bathrooms, and food preparation areas. In commercial settings such as cafes, restaurants, and food storage facilities, a German cockroach sighting is taken seriously because of how quickly the population can grow. It is the species most commonly associated with cockroach activity in Melbourne kitchens and Sydney food businesses.

Identification

• Notorious for their world-wide distribution, German cockroaches are easily identifiable by 2 dark longitudinal stripes on their pronotum. Adults grow to approximately 12 – 15mm in length.

Life cycle and habits of the German Cockroach

Lifecycle

• Females carry 35 – 40 eggs in an ootheca (egg case) until they are ready to hatch.
• Hatch in 1 month.
• Nymphs take between 6 weeks to 6 months to develop into adults.
• Generally 3-4 generations per year.

Habits

• Most commonly found indoors.
• Prefers wet, humid conditions and are typically found in kitchens and bathrooms in homes and commercial properties.

Why is the German cockroach so difficult to manage?

The German cockroach reproduces faster than most other pest species and has a tendency to develop resistance to over the counter products over time. DIY treatments may reduce visible numbers temporarily, but they rarely reach nesting sites inside wall cavities, behind appliances, or under cabinetry where the colony continues to breed.

Oriental Cockroach

(Blatta orientalis)

The Oriental cockroach is dark brown to black in colour and grows to around 20 to 25mm in length. The female has very short, underdeveloped wings, while the male's wings cover approximately three quarters of the abdomen. Neither sex flies readily. This species runs rather than flies.

Where does the Oriental cockroach live?

This species is well adapted to cool, damp environments and is most commonly found in drains, basements, subfloor areas, and beneath porches. It tends to feed on decaying organic matter and is frequently found around rubbish areas and leaf litter. In Australian cities, the Oriental cockroach is more common in older homes with subfloor access or properties with drainage issues.

Identification

• Dark brown or black in colour.
• 20 -25mm long.
• The wings undeveloped in female and cover ¾ length of the abdomen in the male.

Life cycle and habits of the Oriental Cockroach

Lifecycle

• Females deposit 16 eggs in an ootheca (egg case).
• Hatch in 2 months.
• Nymphs take 6-18 months to develop into adults.

Habits

• Highly adapted for surviving in the natural environment, Oriental cockroaches thrive in cool, damp areas such as basements, drains and openings beneath porches.
• Known for their preference for feeding on garbage and decay, these insects can most commonly be found in rubbish tips and leaf litters.
• Runs rather than flies.

American Cockroach

(Periplaneta americana)

The American cockroach is one of the largest pest cockroach species found in Australian properties, growing to between 35 and 40mm in length. It is shiny reddish brown in colour with a pale yellow band around the pronotum. Male wings extend slightly past the abdomen; female wings just overlap. It typically runs but may fly in very high temperatures.

Where does the American cockroach live?

Also known as the 'Palmetto bug' because they live on trees, the American cockroach favours dark, humid, and undisturbed spaces. It is commonly found in subfloors, basements, roof voids, kitchen areas, and drainage systems in both homes and commercial buildings. In Sydney and Brisbane, it is often found entering homes through sewer drains and pipework.

Identification

• 35 - 40mm long.
• Shining red–brown in color.
• Wings longer than the body in male; only just overlap abdomen in female.
• Runs (may fly at very high temperatures).

Life cycle and habits of the American Cockroach

Lifecycle

• The ootheca (egg case) containing up to 16 eggs is carried by the female for several days before being deposited. Sometimes cemented down and tend to be grouped.
• Hatch in 1 – 2 months.
• Nymphs usually develop in 6 -12 months, but it can take up to 15 months.

Habits

• Also known as the ‘Palmetto bug’ because they live on trees, the American cockroach prefers dark, humid and undisturbed areas and can be found in subfloors, basements, kitchens, roof voids and bathrooms of homes.

Brown Banded Cockroach

(Supella longipalpa)

The Brown Banded cockroach is one of the smallest pest species found in Australian homes, with adults measuring approximately 10 to 15mm in length. It is light brown with two distinctive pale yellow bands across its abdomen, which give the species its name.

Where does the Brown Banded cockroach live?

Unlike most cockroach species, the Brown Banded cockroach does not rely on moisture and can be found in drier areas of the home. It is commonly found in ceilings, attics, inside and around appliance motors, behind picture frames, and inside furniture. It prefers materials with a high starch content, including book bindings, wallpaper paste, and cardboard packaging.

Identification

• One of the smallest pest cockroaches, brown banded adult cockroaches are approximately 10 – 15mm in length and characterised by yellow-brown stripes across their abdomen.

Habits of the Brown Banded Cockroach

Habits

• Brown banded cockroaches mostly stay on ground, but may fly in very warm climates. Their preference for warm, humid environments leads them to harbourages within heated buildings - ceilings, attics, inside and around appliance motors. Primarily active at night, these opportunistic feeders particularly enjoy materials with high starch contents.

Smoky Brown Cockroach

(Periplaneta fuliginosa)

The Smoky Brown cockroach is a large, shiny dark brown species growing between 30 and 35mm in length. It is uniform in colour with no visible markings, which helps distinguish it from the Australian and American cockroach. Both male and female have wings longer than the body and are capable fliers.

Where does the Smoky Brown cockroach live?

This species is commonly found in tree hollows, under bark, beneath floors, and in roof voids. It moves indoors at night and is often attracted to outdoor lighting. In Brisbane and other warm, humid parts of Australia, Smoky Brown cockroaches are a common summer sighting around outdoor entertaining areas and garden lighting.

Identification

• 3-35 mm mm long.
• Shining dark brown in colour.
• Wings longer than the body in male; only just overlap abdomen in female.
• Runs (may fly at very high temperatures).

Life cycle and habits of the Smoky Brown Cockroach

Lifecycle

• Females deposit the ootheca (egg case) containing 22-26 eggs a day after production.
• Nymphs take between 6-12 months to develop into adults.
• The noticeable difference between nymphs and adults, apart from size, is the lack of wings in the young.

Habits

• Lives in tree hollows, under bark, under floors, and enters buildings at night.
• Nocturnal (hides during the day in cracks and crevices or any other dark warm places).
• Has a habit of entering houses and contaminating food with excrement, regurgitated salivary fluid and potentially harmful bacteria.

Which cockroach species are most common in your city?

The cockroach species most likely to be active on your property depends on where you live, the type of building you are in, and the season.

Sydney and Brisbane: The warm, humid climate along the east coast makes conditions suitable for the Australian cockroach, American cockroach, and Smoky Brown cockroach. These species are commonly found around roof spaces, gardens, and drainage systems in residential and commercial properties.

Melbourne: The German cockroach is one of the most regularly reported species in Melbourne homes, cafes, and restaurants. Its ability to thrive in heated indoor environments means it remains active year round regardless of the season.

Perth and Darwin: The Smoky Brown cockroach and Australian cockroach are frequently encountered in Perth and across northern Australia, where warm temperatures and humid conditions suit their outdoor habits. They are commonly reported entering homes through gaps in roof voids and weatherboards.

Older homes across all states: The Oriental cockroach is more commonly found in older properties with subfloor access, drainage issues, or cool, damp basement areas.

If you are unsure which species is present on your property, a professional inspection is the most reliable way to get an accurate identification and a management plan suited to your specific situation.

What health risks do cockroaches pose?

Cockroaches are known carriers of bacteria including Salmonella, E. coli, and Listeria. They pick up pathogens in drains, sewers, and rubbish areas and transfer them to food preparation surfaces, utensils, and stored food as they move through a property.

Their droppings, shed skins, and saliva contain allergens that can trigger asthma attacks and allergic reactions.

This is a particular concern in households with children, elderly residents, or anyone with existing respiratory conditions.

In food businesses, a cockroach sighting can have serious consequences for health compliance and reputation. German cockroaches, in particular, are associated with food safety incidents in commercial kitchens due to their tendency to harbour close to food sources and their rapid reproduction rate.

Cockroach pest control services

Identifying the species is a useful starting point. Taking action quickly is what matters most. Here are some practical steps to reduce the conditions that attract cockroaches indoors:

• Seal gaps and crevices around doors, windows, pipe entries, and foundations to limit access points
• Keep kitchens and bathrooms clean and dry; fix any leaking taps or pipes
• Store food in sealed containers and dispose of rubbish regularly
• Declutter storage areas, particularly piles of cardboard, paper, and packaging
• Clean behind and under appliances regularly, especially in kitchens

These steps can reduce the conditions that attract cockroaches, but they may not be enough once an infestation has taken hold.

When should you call a professional?

Cockroach infestations are often more advanced than they appear. For every cockroach spotted during the day, there are typically many more sheltering in wall cavities, behind appliances, inside roof voids, and beneath flooring.

DIY products can reduce visible numbers in the short term, but they rarely reach the harbouring sites where cockroaches breed and shelter. Without addressing those areas, numbers tend to recover quickly.

Rentokil's licensed pest control technicians identify the specific cockroach species on your property and carry out targeted treatments suited to that species' behaviour and hiding locations. Whether it is a home, restaurant, warehouse, or office, Rentokil has been managing cockroach activity across Australian properties for over 50 years.

Book an inspection or treatment with Rentokil today.