Farmers are desperately seeking a new release of the calicivirus after its failure to eradicate rabbits in wetter areas.

They are calling on the Department of Natural Resources and Environment to act urgently as rabbit populations continue to increase.

The first release of the virus has been described by some farmers in southern and western areas of Victoria as a disaster.

Victorian Farmers Federation land use committee executive officer Jon Pitt said the success of the calicivirus was patchy.

"It has been very successful in the drier areas and not so good in others," he said.

Woady Yaloak Catchment Group project officer Cam Nicholson said calicivirus had no effect in his district, which includes 48,000 hectares south of Ballarat near Pittong, Rokewood and Cape Clear.

"We expected a big bang and dead rabbits around everywhere and that certainly didn't happen," he said.

"No one seems to understand how it spreads and I think we need to know how it works before it is re-released."

Chatsworth Merino wool producer Belinda Winter-Irving said calicivirus had been ineffective because it hadn't spread from release sites.

"The only rabbits that have died here are from our 1080 carrot baiting in January," she said.

"Calicivirus is supposed to have come through this area but if it did, it didn't do anything."

Bellarine Peninsula farmer Graeme Brown said the department should have released the virus at more sites to ensure widespread eradication.

"On some of the farms I sharefarm, rabbits are still a real problem," he said.

"It needs to be re-released because in hindsight calicivirus has been a disaster."

A Federal Bureau of Resource Sciences report found a reduction of 65 per cent of rabbit numbers had occurred in 17 per cent of broad-scale monitoring sites where the virus was introduced by inoculation, compared with 76 per cent where the virus spread naturally.

Calicivirus has been released at 120 sites in Victoria and has been less effective in the wetter areas of the state, according to the DNRE.

The department confirmed further releases were unlikely.

Its Mallee pest animal co-ordinator, Laurie Hocking, said the virus had spread well in dry areas, killing up to 95 per cent of rabbits on some properties in the state's north.

John Hardiman, the marketer of the Victorian-developed Rid-A-Rabbit, a rabbit killing invention using LP gas, said farmers desperate to control rabbit plagues were calling him regularly.