The price of organic food could increase because of new rules about GM content, campaigners warned today.

EU agriculture ministers last week agreed that food accidentally contaminated with up to 0.9% genetically modified content could be labelled "GM free".

But the Soil Association and Organic Farmers And Growers, which together certify more than 90% of the UK's organic food, today pledged to keep their own criteria at the current 0.1 per cent.

Maintaining this standard could incur extra costs to farmers and growers which in turn would push up prices, the Soil Association warned.

It wants GM firms to foot the bill for clearing up any future contamination of organic produce above the 0.1 per cent threshold.

Policy director Peter Melchett said organic producers and farmers were concerned.

"Either the cost to consumers will go up or they will lose the trust of consumers and their sales will go down," he said.

Delegates from the Soil Association and a group of organic businesses are meeting Environment Secretary David Miliband to discuss the issue today.