Fire ants: what to do if you suspect them

If you suspect fire ants, don't spray, dig or disturb the nest. Keep people and pets away, photograph it from a safe distance, and ring the Ministry for Primary Industries pest and disease hotline on 0800 80 99 66. Fire ants are notifiable organisms in New Zealand and are not established here; every suspected find is investigated. Treating them yourself can scatter a nest and make it harder to find every queen.

Why fire ants are treated so seriously

Fire ants are among the most damaging invasive ants in the world. They sting painfully and repeatedly, can cause serious allergic reactions, attack wildlife and livestock, damage crops and get into electrical equipment. Countries where they have established spend large sums every year controlling them. New Zealand has so far kept them out.

The Biosecurity (Notifiable Organisms) Order 2016 lists three fire ants: the red imported fire ant (*Solenopsis invicta*), the tropical fire ant (*Solenopsis geminata*) and the little fire ant (*Wasmannia auropunctata*). Notifiable means anyone who suspects their presence must report it.

Past incursions in New Zealand

Fire ants have reached New Zealand before and been eradicated. Te Ara records the red imported fire ant being found and eradicated three times. Ministry of Agriculture and Forestry reporting, reproduced by the Farm Forestry Association, describes a find at Port of Napier in 2004 and another at Whirinaki in Hawke's Bay in 2006, both eradicated. An Auckland Airport find in 2001 is also reported.

Each was found because someone noticed something odd and reported it. That's the system working, and why a call to MPI is never wasted.

How fire ants differ from Auckland house ants

Most ants you see in Auckland are not fire ants. Argentine, black house, white-footed and Darwin's ants don't sting people and don't build mounds of loose soil. Fire ants differ in several ways at once, and it's the combination that should make you suspicious.

• small, reddish-brown to dark ants of varying sizes in the same nest
• a painful, burning sting, often several stings at once
• mounds of loose, fluffy soil in sunny open ground such as lawns and verges, with no obvious entrance hole on top
• ants that boil out aggressively when the mound is disturbed

Some native and introduced ants are reddish. Colour alone isn't enough; the stinging and the mound are the key signs. Telling house ants apart covers the common species.

Where fire ants might turn up

Past incursions have been linked to ports, airports and imported goods. Fire ants travel in soil, on machinery, in containers and with plants. In Auckland, the places to watch are around ports, freight yards, nurseries, new landscaping and anywhere imported equipment or soil has been used. That said, a suspected nest anywhere should be reported.

What to do, step by step

1. Keep people and pets away from the nest.
2. Don't spray it, pour anything on it, dig it up or kick it.
3. Take photos from a safe distance, including something for scale.
4. Note the exact location.
5. Ring MPI on 0800 80 99 66.
6. Follow MPI's advice about collecting a sample; only do so if it's safe.

MPI's guidance is to photograph a suspected mound, collect a sample only if safe, and call the hotline.

Why we won't treat suspected fire ants

A pest control treatment on a suspected fire ant nest could kill some ants and scatter others, making it harder for biosecurity officials to find every queen. It also delays the official response. That's why no responsible technician will treat a suspected fire ant nest. If a technician sees one during an ordinary ant visit, they'll stop and report it.

This is one of the few situations where the right call is not a pest controller at all. See the service for the other things we won't do and why.

If you've been stung

If someone has been stung many times or shows signs of an allergic reaction, such as swelling of the face or throat or difficulty breathing, ring 111. For advice on stings and first aid, ring Healthline or your doctor. Ordinary Auckland house ants don't sting people.

Ordinary ant problems

If it turns out not to be fire ants, you're back to an ordinary ant problem. Mounds of soil in the lawn or between pavers are usually harmless nests of introduced or native ants. See lawns, paths and pavers. Published Auckland prices for one area or a small home start at about $210 to $255 incl GST.

Checked 5 November 2026