Most ants in Australian homes respond to professional baiting. Common types -- White-footed house ants, Argentine ants, Coastal brown ants -- can all be treated. A licensed pest controller finds the nest and uses registered products. That's more effective than surface spraying. health.vic.gov.auView source health.vic.gov.auView source
Three species need a different approach. Don't spray Pharaoh's ants -- it breaks the colony into new groups and you'll end up with more ants. Singapore ants can chew through wiring, which is a fire risk. Carpenter ants nest in decaying timber and often signal a moisture problem. If you think you've found fire ants, don't treat them. Report to 13 22 68 or fireants.org.au right away. health.vic.gov.auView source business.qld.gov.auView source
The ant type you have changes what works -- and what makes things worse
Most common ants in Australia respond well to professional treatment. White-footed house ants, Argentine ants, Coastal brown ants, and Black house ants can all be treated with sprays, dusts, or baits. health.vic.gov.auView source
Three species are different. Spraying them makes things worse.
Pharaoh's ants (light yellow-brown, 1.5-3mm) must not be sprayed. Spray breaks the colony up. Workers scatter and start new groups -- a process called budding. You end up with more ants. These ants are common in blocks of flats, hospitals, and food businesses. They spread through wall voids. Only professional baiting works. health.vic.gov.auView source
Singapore ants (1.5-3mm, can sting) are drawn to electrical gear and plastics. They chew through wiring. That's a fire risk. Spraying the surface won't reach the nest. A pest controller finds it and treats the source. health.vic.gov.auView source
Carpenter ants (2.5-14mm, brown, usually active at night) nest in damp or rotting timber. If they're coming out of your walls, there's often a moisture or timber decay problem involved as well. health.vic.gov.auView source
Ant species quick-reference: what to do
Use this table to identify the most common ant types found in Australian homes and the recommended action for each.
| Ant type | Size | Key sign | What to do |
|---|---|---|---|
| 2.8-3.5mm, shiny black | White-footed house ant | Active at night; sweet food attracted; may bud if disturbed | Professional spray or bait treatment |
| 1.5-3mm, slender brown | Argentine ant | Multiple queens, no soldier caste; primary food is honeydew from aphids | Professional bait treatment; large interconnected colonies |
| Workers 1.5-3mm; soldiers 3.5-4.5mm | Coastal brown ant | Multiple queens, interconnected nests; relatively painless sting | Professional spray or bait to all nest sites |
| 2.5-3mm, intensely black | Black house ant | Strong odour when crushed; bites but doesn't sting | Professional spray on ant paths and nesting sites |
| 1.5-3mm, light yellow-brown | Pharaoh's ant | Multiple queens; common in hospitals and food-service buildings | Do NOT spray. Professional bait only -- spraying fragments colony |
| 1.5-3mm, can sting | Singapore ant | Attracted to electrical equipment and plastics; can chew wiring | Call a pest controller immediately -- wiring damage is a fire risk |
| 2.5-14mm, brown to pale brown | Carpenter ant | Nests in decaying or damp timber; nocturnal | Professional treatment; also investigate moisture or timber decay |
| 2-6mm, coppery brown | Fire ant (Solenopsis invicta) | Flat soil mounds or mounds up to 40cm; painful burning sting | Do NOT treat. Report to 13 22 68 or fireants.org.au immediately |
Species identification should be confirmed by a licensed pest controller. Treatment must use APVMA-registered products applied by a licensed operator.
Fire ant? Do not treat it yourself -- report it now
Fire ants are a category 1 restricted pest under the Biosecurity Act 2014. If you think you've found fire ants, you must report them. Don't treat them yourself. business.qld.gov.auView source
What to look for: coppery-brown ants, 2-6mm, with a darker abdomen. Nests can look like flat, disturbed soil or mounds up to 40cm high. You'll find them in lawns and garden beds. Fire ant stings burn and itch for up to an hour. Multiple stings can cause pustules that get infected if scratched. business.qld.gov.auView source
Don't disturb the nest. Don't spray it. Don't move soil or garden material from the area -- biosecurity zone rules apply. Report right away: call 13 22 68 or go to fireants.org.au. The National Fire Ant Eradication Program handles the treatment. business.qld.gov.auView source
Why ants come inside -- and why spraying the trail doesn't fix it
Ants live in permanent nests. The ants you see on your bench are foragers. They leave the nest to find food and water. The nest is outside, or in a wall void, under a slab, or beneath paving. Spraying the trail kills foragers -- but the nest keeps sending more. Most colonies have thousands of workers. health.vic.gov.auView source
What draws them in: food scraps on bench surfaces, uncovered pet food, sweet spills, dripping taps, and damp subfloors. Ants can find sugar in amounts too small for us to notice. A bench that looks clean can still attract them. health.vic.gov.auView source
Cleaning up food helps. It reduces how many ants come foraging. But it won't kill an established colony. For a lasting fix, a pest controller finds the nest and treats it. That's the most effective approach. health.vic.gov.auView source
When you need a licensed pest controller for ants
A licensed pest controller knows which product works for which species. They treat the nest directly -- that's where the colony lives. For some ant types, it's the only safe option. health.vic.gov.auView source health.vic.gov.auView source
Call a pest controller if you have: ants coming back after DIY treatment; ants coming out of walls or ceiling voids; Pharaoh's ants in a flat, food business, or aged care facility; Singapore ants near electrical fittings; Carpenter ants in timber frames; or any fire ant suspicion (report first, don't treat). health.vic.gov.auView source health.vic.gov.auView source
Pest controllers are licensed to treat ants. They cover spiders, cockroaches, ants, fleas, mites, and other common pests. They carry a photo ID licence and use registered products. health.vic.gov.auView source betterhealth.vic.gov.auView source
What a professional ant treatment involves
The controller will confirm the species first. Then they'll choose the right product. Sprays go on travel paths -- cracks in paths, skirting boards, door frames. Dusts go in spots where sprays aren't safe, like electrical boxes. Baits are used when the nest can't be found. Foragers carry the bait back. The whole colony picks it up. health.vic.gov.auView source health.vic.gov.auView source
Before the visit: cover food, pet bowls, kids' toys, and bedding. Move pets out during treatment. After treatment, wait four to six hours before you go back in. Let the products dry. betterhealth.vic.gov.auView source
Bait treatments take time. It can take a few days for the colony to go. Don't clean treated surfaces in that period. Cleaning removes the bait before it can work.
How much does ant pest control cost?
Cost depends on the ant species, nest location, property size, and whether a follow-up visit is needed. A licensed pest controller will quote based on your specific situation.
Common questions about ant control
The most effective approach is direct nest treatment by a licensed pest controller. Surface sprays don't reach the colony. For the best result, combine professional treatment with good hygiene: seal food, fix leaking taps, and clear debris near the home.
Ants come inside to find food and water. They're drawn in by food scraps, pet food, sweet spills, and moisture from dripping taps or damp subfloors. The trail you see connects to a nest outside or in a wall void. Cleaning up food helps, but won't remove an established nest.
Yes. Licensed pest controllers treat ants as part of their general pest licence. They'll identify the species, find the nest where they can, and apply the right treatment -- spray, dust, or bait. Ants are one of the most common jobs.
Yes. Fire ants are a category 1 restricted pest under the Biosecurity Act 2014. If you find a suspected fire ant nest, you must report it. Don't treat it yourself. Call 13 22 68 or visit fireants.org.au. Don't touch the nest or move soil from the area. The National Fire Ant Eradication Program handles treatment.
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Sources
- health.vic.gov.auView source
- health.vic.gov.auView source
- business.qld.gov.auView source
- betterhealth.vic.gov.auView source