An invasive ant species capable of causing blindness and decimating crops has been discovered infesting the CBD of a town on the north coast of New South Wales.

Key points: Yellow crazy ants are recognised by their pale yellow colour, unusually long legs and antennae.

Yellow crazy ants are recognised by their pale yellow colour, unusually long legs and antennae. Their name is derived from their frantic movements and frequent changes in direction, particularly when disturbed.

Their name is derived from their frantic movements and frequent changes in direction, particularly when disturbed. The ants use a formic acid to overpower and destroy prey very quickly.

The ants use a formic acid to overpower and destroy prey very quickly. They're known to build super colonies with several queens which can expand rapidly and in some cases double in size in just 12 months. Source: NSWDPI

Department of Primary Industries and Local Land Services staff have confirmed the presence of yellow crazy ant in Lismore and have begun a surveillance and identification operation.

It is the first time in more than a decade the destructive species has been found in New South Wales, since it was eradicated from Goodwood Island in the Clarence River in 2008.

James Cook University invasive species expert Lori Lach said an outbreak of yellow crazy ant was a serious concern.

"It is considered one of the world's 100 worst invasive species," Dr Lach said.

"It is an aggressive ant; it can reach extremely high population densities.

"It does spray formic acid, and although there are other species of ant that also spray formic acid, this acid — either because the ants are so numerous or because there's something potentially potent about their acid — can do quite a lot of damage."

Farmer temporarily blinded

Frank Teodo and his dog both suffered acute pain and blindness after being attacked by yellow crazy ants. ( ABC Rural: Charlie McKillop )

Queensland resident and cane worker Frank Teodo said he was temporarily blinded by yellow crazy ants.

The Edmonton landholder said the ants wreak havoc on the environment, lifestyles and the health of people and their pets.

"I had them on my property for quite some time," he said.

"They build up in sufficient numbers, I couldn't control them — I had a cocktail of chemicals around my house that would have knocked out anything.

"They don't actually bite, but they spray formic acid, so they can blind your pets, they'll blind you if you get them near your eyes.

"I've had them on my face causing all sorts of damage. They're a terrible, terrible pest."

He said the yellow crazy ants protect and feed off the honey dew of pests like mealie bugs and aphids, which causes an "explosion" of pests that damage crops like cane.

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Authorities baffled by ant arrival

The introduced species are thought to have originated in Africa, and arrived accidentally in Australia in the 1950s.

They were first detected in Queensland in 2001 and the Goodwood Island outbreak is thought to be the only case in New South Wales — until this week.

Dr Lach said Goodwood Island was considered a small infestation, spanning about 150 x 100 metres.

In contrast, DPI staff said the latest outbreak appears to span the majority of Lismore's CBD.

Department of Primary Industries regulatory officer Kathy Goulding, who is working on the infestation in Lismore, said the ants have caused havoc on native wildlife in Queensland.

"They're decimating a lot of ground-dwelling birds and smaller insects and lizards and things like that," she said.

In the 1990s, yellow crazy ants were thought to have killed tens of millions of red land crabs on Christmas Island.

Ms Goulding said it wasn't clear yet how the pest arrived in Lismore.

"At this stage, we don't know how they got here — that's one of the things we're looking into," she said.

NSW DPI regulatory officer Kathy Goulding says staff have begun a surveillance and identification operation. ( ABC North Coast: Leah White )

Serious implications for horticulture

Ms Goulding said if yellow crazy ants were found to be widespread, it could have serious ramifications for the farms and businesses that surround Lismore.

"They'll eat the plants and eat the roots and eventually there'll be less and less crop," she said

DPI Biosecurity and Food Safety Director of Invasive Plants Andrew Sanger said it was a member of the community who spotted the outbreak in Lismore and reported it through the DPI biosecurity hotline.

He said the ants could spread very quickly, build super colonies and damage local ecosystems.

"If you see these ants — yellow or brownish, about 5mm long, with very long legs and antennae and an erratic walking style — you can report them on the Biosecurity Hotline, the DPI website, or via the Local Lands Services office."

The Yellow Crazy Ants are recognised by their pale yellow colour, unusually long legs and antennae. ( ABC North Coast: Leah White )

Dr Lach said humans were the most common cause of transporting yellow crazy ants.

"When we're talking about most of the spread all over the world, so globally and also locally, it's humans, it's humans moving around contaminated materials," she said.

"Globally I would expect a lot of the timber products coming out of South-East Asia would have a high probability of containing yellow crazy ants.

"Locally we know that people moving their contaminated yard-waste is a really common way."