A former Qantas steward who believes he developed Parkinson's disease after repeated exposure to government-mandated pesticides sprayed in the cabin plans to sue Canberra, his lawyer said Monday.

Brett Vollus, 52, worked for Australia's national carrier for 27 years as a flight attendant until his early-onset Parkinson's forced him to take redundancy in May this year.

Vollus engaged a specialist lawyer, Tanya Segelov, to look into his case after the Sydney neurosurgeon who made his diagnosis told him he was seeing "a lot" of cabin crew.

"He has no family history of Parkinson's and he believes the Parkinson's has been caused by his exposure to the insecticide that he sprayed as a long-haul flight attendant on at least a fortnightly basis over a period of 17 years when working on board aircraft," Segelov told AFP.

"There is a link in the medical literature between Parkinson's and other motor neurone disease and insecticide, and that link is well established," she added.

The spraying was mandated by the Australian government on World Health Organization guidelines to prevent the spread of insect-borne diseases such as malaria.

Known as "aircraft disinsection", such spraying has been an international practice since the 1920s and the first WHO directives on the subject were published in 1961.

Australia's health department said its disinsection programme was in line with WHO requirements and all products used had been assessed as safe, both internationally and by the Australian Pesticides and Veterinary Medicines Authority.

"The WHO has found no evidence that disinsection sprays, when used according to their guidelines and manufacturers' instructions, are harmful to human health," a department spokesman told AFP.

Without such spraying programmes, the spokesman said Australia's freedom from serious diseases such as yellow fever and malaria could be at risk.

Segelov won an engine fumes suit in 2010 against East-West Airlines, a regional carrier of now-defunct Ansett Australia, on behalf of a flight attendant who suffered respiratory damage. She said Vollus's case could have national or even global implications.

"This is not an issue confined to Australia, and there are still countries that mandate this spraying as well," she said.

"Some Asian countries still do it, India definitely still does."

Australia's Transport Workers' Union said it would consider filing a class action on behalf of the nation's aircraft workers if a health link could be established with insecticides, urging anyone with such concerns to come forward.

"Imagine spraying household insecticides in a small room each day, then spending the day working in that room," said TWU secretary Tony Sheldon.

"When you're flight crew or cleaners, you have no choice. You're sucking these chemicals into your lungs every working day."

Segelov said Vollus's case would hinge on whether the government knew of the potential risks to cabin crew, or should have known.

The lawyer said practices had since evolved to allow spraying to take place once the aircraft was empty, in a hangar, and for the personnel carrying it out to wear protective gear.

"As I understand it from looking at the World Health Organization requirements that option has always been available," she said.

"From the research I've done I think (the Australian government) were the ones that made the decision to spray on board the planes and they did it in such a way with no protection was offered to my client -- he had a can in each hand, he couldn't even cover his mouth."

Qantas said it complied with law and the issue was a matter for the government.