Supermarket Woolworths has committed to purchase "deforestation-free" beef from the end of next year.

Announcing its financial results on Wednesday, the retailer updated its sustainability target, shifting from an existing net-zero deforestation goal, to become "deforestation-free" by the December 2025.

The policy will be applied to fresh beef, paper, pulp and timber, palm oil, cocoa and soy sold across its stores.

But its not yet clear how deforestation-free will be defined for cattle producers selling beef to the supermarket, which accounts for about 7 per cent of all beef processed in Australia.

"We are committed to sourcing beef sustainably in partnership with our farmers and suppliers," a Woolworths spokesperson said.

"We believe our no-deforestation goal will help promote the already strong sustainability credentials of Australian red meat, and expect all our suppliers to adhere to all federal and state land management laws".

It's not yet clear how "deforestation-free" will be regulated or applied.

"We support the development of a localised definition which recognises Australia's unique landscape and vegetation, while ensuring responsible land management," the retailer said.

In its sustainability statement, Woolworths said its approach to the target would be "grounded in principles of a just transition" and it would continue to work with beef producers "in pursuit of a geographically appropriate definition of deforestation that meets global regulatory requirements and corporate deforestation targets."

Cattle Australia, which represents farmers that raise pasture-fed cattle, welcomed Woolworths' commitment to work with producers to define its sustainability terms for the Australian context.

Its spokesman, Chris Parker, said Australian farmers "already operate under some of the toughest and most extensive vegetation management laws in the developed world (and) this move was a win for producers and the environment".

Conservation groups have welcomed Woolworths' commitment to switch from net-zero deforestation to deforestation-free.

"No one sells more beef to Australians than Woolworths, so this commitment has enormous implications for nature and for people who want to make sustainable food choices," said Australian Conservation Foundation spokesman Nathaniel Pelle.

"While most graziers are not engaged in broadscale bulldozing of bushland, Australians can't choose deforestation-free beef because supermarkets don't differentiate.

"With this commitment, which follows a similar commitment from Aldi, that is changing."

Instead of a deforestation-free policy, Coles supermarket has a "net-zero" deforestation target. 

That allows for deforestation, so long as it is "offset" by tree planting elsewhere.

A spokesperson for Coles told the ABC it was engaged with environmental groups on a broad range of nature-related issues.

"We recognise the complexity of addressing the nature challenge and are committed to working with our farmers, suppliers and industry partners to reduce our impact on the environment and help our customers to make more responsible choices," the Coles spokesperson said.