Just a week after several of the UK's biggest consumer brands were accused of contributing to the destruction of the rainforest through their use of palm oil sourced from illegal plantations, supermarket giant Sainsbury's has sought to distances itself from the controversial practice.

The company has announced a ban on all palm oil from unsustainable sources used in its own brand products. It will now only accept palm oil from certified sustainable sources and will announce a deadline for the complete phase out of uncertified palm oil in its products by early next year.

The first food on UK supermarket shelves to contain certified sustainable palm oil will be Sainsbury’s Basics Fish Fingers that will convert by May 2008, while sustainable palm oil will also be used in soap from July next year. The company also committed that it will label all fresh and chilled foods that contain palm oil from next summer, giving shoppers greater transparency over what they are consuming.

Judith Batchelar, director of the Sainsbury's brand, said that the company was committed to working with suppliers to avoid deforestation and improve the sustainability of palm oil. "Rather than banning the use of palm oil, we want to find a sustainable solution that will stop deforestation while continuing to support the communities that rely on its production," she said.

The announcement comes as palm oil industry group the Roundtable for Sustainable Palm Oil (RSPO) meets in Malaysia to discuss proposed criteria for certifying sustainable plantations. The standards would commit members of the industry group to a number of environmental and ethical best practices, including compliance with all local laws, sustainable agricultural methods and ethical employment policies.

Adam Harrison, senior policy officer for food and agriculture at the WWF, welcomed the Sainsbury's announcement and urged other companies to "follow suit and commit to using only Roundtable on Sustainable Palm Oil (RSPO)-certified palm oil".

However, some environmentalists are likely to remain concerned about both Sainsbury's capacity to source sufficient sustainable palm oil and how well any standards will be policed. A report from Greenpeace released earlier this month linking Nestle, Unilever and Procter & Gamble with palm oil providers guilty of clearing tropical rainforest noted that at least one member of the RSPO, Duta Palma, is "engaged in illegal activities, including the large-scale clearance and destruction of deep peat lands protected under Indonesian law".

Greenpeace campaign manager Andy Tait said that Sainsbury's was looking for a short term fix by shifting its supply away from south east asia, but warned that in the longer term it would need to push the RSPO for more stringent standards if iot wanted to be sure it was sourcing sustainable palm oil.

"This looks like a tactic to push the RSPO to take more action and that has to be good," he said. "There is urgent need for Sainsbury's and other retailers to send a strong message through their supply chain that this has to be resolved and the RSPO must support a moratorium on forest clearance, which it does not at the moment."