Farmers are being encouraged to maintain strict biosecurity practices after a suspected case of Panama TR4 disease - a soil fungus, was detected at a far north Queensland banana farm.

The disease is the biggest biosecurity threat to Australia's $580 million banana industry and eradication of the disease is not feasible.

The Tully Valley property, south of Cairns, where the latest case has been detected is close to three other properties infested with the disease first found in Queensland in 2015.

There has been a positive preliminary test for the disease but it could take up to four weeks for a conclusive result, Biosecurity Queensland's Rhiannon Evans said.

The fungus attacks the banana's vascular system causing wilting and death of the infected plant.

It has been estimated that 80 per cent of global production is under threat from the fungus, federal authorities say.

The Queensland government has so far spent $42 million to manage the disease in the state's far north.

The industry knew the disease would eventually spread but it's still bad news, says Australian Banana Growers' Council Chair Stephen Lowe.

"This is definitely news that no one in our industry wanted to hear," Mr Lowe said.

"First and foremost, our thoughts are with the grower affected.

"This is no doubt going to be a challenging time for them and their family, and we will look to help them through this in any way we can."

Queensland accounts for more than 90 per cent of Australia's banana production with most of the farm's based in the state's far north.

People and machinery movement are the biggest threat of disease spread but heavy rainfall and flooding can also see it move.

The disease is not harmful to humans and does not affect the fruit.

Australian Associated Press