A suspected third case of a highly devastating banana disease has been discovered in far north Queensland, in the country's biggest banana growing region.

In a worrying sign for the industry, samples from a farm in the Tully Valley taken last week have tested positive for Panama disease tropical race 4.

More than 80 per cent of Australia's bananas are grown in the region.

The Department of Agriculture and Fisheries' Mike Ashton said further testing would be performed to confirm the case, which could take up to six weeks.

"Biosecurity Queensland will commence high intensity surveillance on the suspect property to determine the possible extent of the disease, and conducting tracing and on-farm investigations to determine potential risk pathways," he said.

"We are in contact with the business owner and our main focus is to minimise any production downtime for their property."

The department says the suspected new case is in "close proximity" to the two previously confirmed infested properties in the region.

The disease does not affect the fruit itself, but rapidly kills Cavendish banana plants.

The department says the farm is close to the previously infested properties. ( ABC News: Casey Briggs )

The most recent case of the disease was found in July last year at a property owned by Mackays, one of the largest growers in the country.

The property the fungus was first discovered on in 2015 was bought out by the industry and shut down.

Australian Banana Growers Council president Stephen Lowe said it was "highly likely" the subsequent tests will confirm the case.

"I'm sure it is disheartening to a lot of growers, and certainly from an industry point of view it's disappointing," he said.

"But we still have to look on the positive side, we still have a functioning industry, a very vibrant industry, and our goal is to try and keep it that way.

Strict quarantine restrictions are in place on farms in the area. ( Landline: Marty McCarthy )

"The rate of spread has still been extremely slow compared to worldwide experience.

"What we have been doing is working, just not as well as we would've liked."

In order to continue to trade, the farmers affected must abide by biosecurity protocols.

"The farmers involved had already taken some steps towards that so we do expect they'll be able to achieve this," said Mr Lowe.

"The bananas are completely safe to eat, and the best thing the public can do to help the industry is to keep eating them."

Authorities have warned there is no way to eliminate the disease from the soil, and biosecurity efforts have been targeted at containing its spread.