Fire ants have jumped the Queensland border into NSW for the first time since the infestation began.
The NSW Department of Primary Industries confirmed on Saturday three red imported fire ant nests were found in South Murwillumbah, 13km from the Queensland border in the state's northeast.
"This is the first fire ant detection in northern NSW and presumed to be the most southern report of fire ants from the Queensland infestation," the department said in a statement.
Crews are on site working to chemically eradicate the infestation across a radius of 200 metres from the nests.
An emergency biosecurity control order dictates all businesses and residents within a 5km radius of the South Murwillumbah site must restrict the movement of mulch, woodchips, compost, sand, gravel, soil, hay and other baled products.
Agriculture Minister Murray Watt said the Queensland and NSW governments were working to eradicate the detection and monitor surrounding areas.
"This is the first fire ant detection in northern NSW but not the first detection outside southeast Queensland, with isolated detections having previously been eradicated in Gladstone, the Port of Botany and the Port of Fremantle," he said in a statement.
NSW Department of Primary Industries officers and detection dogs were working to determine the extent and origin of the infestation.
Fines for breaches of the biosecurity order can reach up to $1.1 million for an individual and up to $2.2 million for a corporation.
The NSW Farmers Association said the latest incursion posed a threat to agricultural production and called on authorities to act quickly to stem the spread.
"The ants can damage agricultural equipment, sting livestock and damage the natural environment," the association said.
NSW Agriculture Minister Tara Moriarty said the government was prepared for the discovery of fire ants in northern NSW and had immediately implemented the response plan, part of an almost $600 million national eradication program.
She said the government had committed $95 million towards the National Fire Ant Eradication Program.
But Conservation Officer for the Invasive Species Council Reece Pianta said the $592 million allocated until 2027 would not be enough.
"Fire ants are one of the world's worst super pests and, if they are allowed to spread across the continent, their impact will be greater than cane toads, rabbits, feral cats and foxes combined," he said.
"They will devastate Australia's environment and agriculture, cost our economy billions annually and we could see over 140,000 extra medical visits every year.".
Mr Pianta said the spread into NSW should be a wakeup call for the Victorian, Western Australian and South Australian governments yet to commit to their share of funding for eradication.
NSW Nationals leader Dugald Saunders said it was a case of too little too late.
"What we've seen from the state and federal governments so far is a complete lack of urgency, and it's taken the detection of these ants in NSW to trigger an eradication response," he said.
A recent review of the National Red Imported Fire Ant Eradication program warned all hopes would be "lost forever" if the ant moved across the Queensland border into NSW.
Australian Associated Press