$54m for NSW farmers to fight mouse plague

New South Wales farmers could have access to the strongest poison in the world as part of a $A50 million ($NZ54 million) relief package to deal with a mouse plague that's been destroying crops and wreaking havoc since last year.

The NSW Farmers Federation had been agitating for government help for months. Some farmers have already spent more than $A150,000 on baiting, while others have lost more than $A250,000 worth of grain and fodder.

NSW Agriculture Minister Adam Marshall announced the package on Thursday, saying farmers would soon be able to have their grain chemically treated for free, to protect crops.

Affected rural households will also be able to apply for rebates of up to $A500 and small businesses will be eligible to claim up to $A1000 through Service NSW.

"Beyond the paddock, we're going to actually provide rebates for small businesses and for households whether they're on farms or in rural towns to help them with the cost of all the baits that they're buying and traps to try and get on top of this scourge," he told Sydney radio 2GB on Thursday.

The government will also source poison to be provided to farmers at facilities in the hardest-hit areas.

The NSW government is seeking urgent approval from the Australian Pesticides and Veterinary Medicines Authority for approval to use bromadiolone - a new poison outlawed in Australia.

"It's actually the strongest mouse poison we can get anywhere on the face of the earth," Mr Marshall said.

"It will actually kill these things within 24 hours not the (usual) three-day strike down period."

Research within the agriculture department will also be ramped up for a long term solution to mice plagues.

"We're looking for the myxomatosis equivalent for mice so that we can actually have a biological control rather than simply trying to poison these things into oblivion," he said.

Myxomatosis was introduced in Australia in the 1950s to keep rabbit numbers down.