Australian biosecurity authorities have confirmed the crippling Panama Tropical Race 4 banana plant disease has been detected on a north Queensland banana farm for the second time this year.

Biosecurity Queensland said late on Thursday that samples taken from a suspect banana plant on the Tully Valley farm, more than one km from the original detection site in March, confirms the deadly soil-borne disease is still present.

The farm was the first in Queensland to be affected by the disease in March and was given permission to resume full operations in April.

Queensland's Chief biosecurity officer Dr Jim Thompson told Australia's national broadcaster on Friday that the positive test result was beyond doubt after the use of a different genetic (PCR) test to the one that wrongly diagnosed a nearby property.

"It's disappointing," Thomson said.

Authorities confirmed with Xinhua on Friday the definitive Vegetative Compatibility Group (VCG) and not the molecular polymerase chain reaction (PCR) was used to confirm the diagnosis.

In late June, Authorities lifted the quarantine surrounding banana farms after a U.S. made molecular PCR test was found unreliable in early assessment of the disease.

The false positives caused widespread destruction and costly disruptions to Australia's banana farms from the false positive tests.

Thomson said they had hoped to contain the original, confirmed outbreak of the disease on Tully Valley farm in the following months of quarantine.

The farm's owners, in a statement to local media, said they had always known of the possibility that the disease had not been completely eradicated.

"They are nevertheless distressed that a further infected plant has been identified," the statement said.

The Panama Tropical Race 4 disease is the biggest threat to Australia's banana industry.

Local media have reported this current strain of disease is the same that wiped the Northern Territory's banana industry almost 20 years ago.