The world's biggest wild abalone fishery, which accounts for 25 per cent of the global annual harvest, may be under threat from a destructive virus, Australian officials said.

The ganglioneuritis virus has been detected in two abalone from waters off Australia's southern island state of Tasmania and tests are under way to determine the extent of the threat.

The virus has already devastated the abalone industry in the nearby Victoria state on the Australian mainland.

"Our current activities are aimed at trying to determine the location and extent of any disease in the wild so we can develop appropriate control measures," Tasmania's chief veterinary officer Rod Andrewartha said in a statement.

Abalone is a rare and expensive shellfish eaten as a delicacy in parts of Asia and regarded as a symbol of wealth in Chinese society.

Tasmania's abalone export industry is worth about €300 million a year.

The abalone virus, which affects the nervous system of abalone and has a high mortality rate, was first detected in Australian waters in 2006 off the Victorian coast.

The virus was recently detected in two abalone processed in a plant on Tasmania's southeast coast.

"We are not seeing signs of contamination within the live holding facility that held the two that tested positive," Tasmanian Abalone Council president Greg Woodham told the Mercury newspaper on Wednesday in Hobart, Tasmania.

Divers were gathering samples from wild abalone for scientific testing.

"We are targeting our surveillance and sampling from the wild fisheries to see if there any signs of this disease out there," said Mr Andrewartha.