Lloyd Klumpp, chair of the National Fruit Fly Council, said experts were debating whether it was possible to maintain pest-free status of all the fruit-growing areas in all states.

"It is a major topic of discussion at the moment ... we are doing a cost-benefit analysis," Mr Klumpp said.

He said with Australian exports of horticultural produce worth $2.5 billion the numbers "looked like" coming out on the side of keeping up the fight.

"It is an ongoing battle, I would not like to say we are giving up anywhere."

Queensland fruit fly, a native species, is declared endemic in most states - Queensland, NSW and most recently in Victoria.

There are outbreaks in South Australia, where border crossing officials still check travellers for fruit, and most concerning are recent discoveries in Perth.

Fruit fly has been has eradicated from Perth seven times since 1989 where it keeps a permanent network of surveillance sites.

Maintaining fruit fly free status allows WA growers access to export markets, such as avocados to Japan and strawberries to Thailand.

Tasmania managed to eradicate a surprise outbreak in 2018.

Mr Klumpp said climate change and the loss of some chemical management tools had created an "evolving situation" of greater pest risk right across Australia.

"Areas where we had never seen Queensland fruit fly before, we are seeing it."

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Millions of dollars supplied by taxpayers and growers has been spent over the years to unsuccessfully combat fruit fly.

One of the more successful programs has been breeding and releasing sterile flies in target areas "which disrupts reproduction and suppresses pest population numbers".

The flies are bred at the National Sterile Insect Facility SITPlus, in Port Augusta, South Australia.

Mr Klumpp said national programs were "investing heavily" into learning more about the biology of the pest.

He said a national fruit fly strategy had been adopted to end the piecemeal approach of the past.

The infestations going beyond orchards are into home backyard trees as well.

Mr Klumpp said research into cold treatment of fumigation of fruit set for export was continuing.

"There are major national impacts from the spread of this pest that is clear."