Labor has scrapped long-held plans to attempt to prevent the growth of genetically modified crops in Western Australia, admitting it is too late to stop their use.

Key points: WA Labor changes long-held policy opposing growth of genetically modified crops

WA Labor changes long-held policy opposing growth of genetically modified crops Party says law implemented last year reducing state control over use of the technology meant it could not be stopped

Party says law implemented last year reducing state control over use of the technology meant it could not be stopped Farmers' lobby welcome policy shift but Greens say Labor "throwing up hands" in defeat

Labor's decision ahead of the March election is a significant backflip on the party's previous policy, having promised to reinstate a ban on the growth of GM crops.

The Barnett Government changed regulations to allow the growth of GM canola in 2010, and hundreds of thousands of hectares of it are now grown in WA each year.

The Government then passed laws last year which reduced the state's control over the growth of GM crops, removing the Agriculture Minister's power to ban the use of the technology in WA.

Labor at first claimed that legislative change would not affect its policy, but Opposition Agriculture spokesman Mick Murray said he now acknowledged the growth of GM in WA could not be stopped.

"There is not much we can do about it," Mr Murray said.

"We understand very clearly that GM is in the ground and very hard to remove."

Mr Murray said Labor would instead focus on "protecting non-GM farmers and the community from GM contamination" and urge the Federal Government to drive "proper food labelling laws".

Farmers welcome move but Greens decry shift as 'giving up'

But the Greens, who have long voiced health concerns over GM crops, said Labor was wrong to decide they could not be stopped.

"Obviously there are some difficulties in cleaning up but to just give up, throw up your hands and allow any GM to be grown is the wrong approach," Greens MP Lynn MacLaren said.

"It seems like a bit of a backflip."

Many pro-GM farmers had feared they would suffer significant financial harm if a government banned the growth of GM crops.

The Pastoralists and Graziers Association (PGA), which has strongly advocated for GM crops over many years, said farmers would be extremely relieved by Labor backing away from its ban policy.

"The grain farmers of Western Australia were deeply worried about Labor's political position on this and annoyed there was no rationality to it," the PGA's Gary McGill said.

"It is wonderful news for WA grain growers that that certainty and security will now be there and the whole matter about the use of this can be put to rest."

The use of GM crops in WA has long been divisive, with claims in some quarters of health impacts, and concerns about potential contamination of non-GM properties.

Those tensions came to the boil in a prominent legal case between Kojonup farmers Steve Marsh and Michael Baxter.

Mr Baxter faced allegations that he was negligent in allowing his GM crop to contaminate Mr Marsh's organic farm.

But the Supreme Court found Mr Baxter had not acted negligently and rejected Mr Marsh's compensation bid.