An influential lobby group has supported looking into setting up a supermarket code of conduct to ensure food suppliers are treated fairly, after a survey found mark-ups of up to 500 per cent on fresh produce.

The Food and Grocery Council, which represents mainly food manufacturers, yesterday spoke out in favour of investigating the concept - promoted by the Green Party in the wake of its survey - but only if the supermarket code set up in Britain in February proves successful.

"It's a model which is worth consideration," said council chief executive Katherine Rich, a former National MP. Green Party food spokeswoman Sue Kedgley said the survey found that supermarkets applied mark-ups of up to 500 per cent, although 100-200 per cent was the range mostly reported by growers.

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