Most ants in a Sydney home are a nuisance, not a danger. The dangerous ones sting, mainly bull ants and jack jumpers, because their venom can cause anaphylaxis, a severe allergic reaction that can swell the throat. Fire ants are dangerous too, but they have not been found in Sydney. NSW has had three fire ant finds, all in northern NSW, and none since July 2025.
Bite or sting: why it matters
The healthdirect guide to ant stings and bites says Australia has over 4,000 kinds of ants. Some bite with their jaws. Others sting with a needle on the tail. A sting pushes venom into the skin, and venom is what can set off an allergic reaction. The small ants on kitchen benches mostly bite or do nothing at all. healthdirect lists the black house ant (Ochetellus glaber), up to 3 mm long and smelly when crushed, as a biter only. Meat ants (Iridomyrmex purpureus) are the biters to respect. They grow to about 10 mm and bite again and again to guard their nest. Meat ants that bite whoever mows past a Milperra side fence are guarding a nest under that lawn, so book ant control in Milperra rather than mowing over the mound.
The stinging ants to watch for
Bull ants. There are about 90 kinds of bull ant in Australia. They grow up to 40 mm long, they are aggressive, and their stings hurt. healthdirect says those stings sometimes cause anaphylaxis. Jack jumpers. A jack jumper (Myrmecia pilosula) is a medium-sized black bull ant with orange legs. It moves with a hopping walk. It is very aggressive, and its sting can cause anaphylaxis. Some people in Australia have died from jack jumper stings. Green-head ants. Green-head ants (Rhytidoponera metallica) live right across Australia, and their stings can cause an allergic reaction. A bull ant nest beside a Bass Hill clothesline puts someone within stinging range every washing day, so book ant control in Bass Hill instead of pouring boiling water down the hole.
How bad can a sting get? healthdirect describes four levels of reaction. 1. Local.
Itching, redness, swelling and heat that last less than a day, with swelling usually under 5 cm.
- Large local. Swelling wider than 10 cm that can take 7 to 10 days to settle.
- Mild whole-body. About 1 in 100 people get hives, flushing or an upset tummy.
- Anaphylaxis. Throat swelling, a hoarse voice, wheezing, chest pain, dizziness or vomiting. For anaphylaxis, use an adrenaline autoinjector straight away if the person has one, then call triple zero (000) for an ambulance. For an ordinary sting, scrape out the stinger with a bank card or fingernail, wash the spot, and hold a cloth-wrapped ice pack on it for 15 minutes. See a doctor if the sting is in the mouth or near the eyes, or if the person has reacted badly to an ant before. Repeat stings can make some people more sensitive. When a Yagoona child who once reacted badly keeps meeting green-head ants on the side path, every trip down it risks another sting, so arrange ant control in Yagoona rather than waiting for the next one.
When a stinging ant nest is too close healthdirect says many stings at once can cause severe pain and a large skin reaction, and large allergic reactions are more common in children than adults.
A nest is worth having removed when it sits where people walk barefoot, where children play, or beside a door, path or sandpit. NSW families with a jack jumper allergy have one more reason to act. Desensitising treatment protects about 9 in 10 people, but healthdirect says it is only offered in South Australia, Tasmania and Victoria.
Why you should not dig out the nest yourself
Ants defend their nest as a team. healthdirect warns that destroying a nest can raise your risk of being stung, and says professionals should remove ant nests. Jack jumpers that keep coming up through the gaps in a Padstow paved courtyard, where the family eats outside, are nesting right under their feet, so call for urgent ant control in Padstow rather than lifting the pavers yourself.
What fire ants look like
Red imported fire ants (Solenopsis invicta) are not native to Australia. healthdirect describes them as red-brown with a darker rear end and 2 to 6 mm long. They bite and can sting over and over. NSW DPIRD adds that they swarm out of a disturbed nest in large numbers and sting at the same time. Size is the first check. A 40 mm bull ant is not a fire ant. Fire ants are small and easy to mix up with common garden ants. You are more likely to see the nest than the ants. It is a mound or flat patch of loose, crumbly soil up to 40 cm high, with no single obvious entrance hole. Nests are common in open grass, bare soil, near water and near newly delivered turf, soil or mulch, and rare inside homes.
Where fire ants have been found in
NSW The NSW DPIRD red imported fire ants page lists three finds in NSW: South Murwillumbah in November 2023, Wardell in January 2024 and Tweed Heads in July 2025. All three are in northern NSW, far from Sydney, and the nests were destroyed. The page says there have been no NSW detections since July 2025.
Before you book help with a nest
For a stinging ant nest near the house, or any ant you cannot name, photograph the ants and the nest from a safe distance. Note where the nest is, who walks past it and whether anyone has reacted badly to a sting. Send those details when you contact the local pest control service in Bankstown, so the technician knows how close people are to the nest.