Supermarkets are introducing measures to help suppliers struggling through the financial crisis.

The major supermarkets have signed up to the government's Prompt Payment Scheme - a voluntary code of practice launched this month by Business Secretary Peter Mandelson to try to ensure firms pay their suppliers on time and do not change terms retrospectively.

Asda has shown further commitment to paying suppliers on time by signing up. It already works with a selection of small suppliers whose payment terms are within 30 days and it also offers a "Pay Me Early" option that allows suppliers to request a one-off early payment.

A spokesman for Asda said: "In today's tough economic climate, this added facility allows suppliers access to short term cash flow, giving them more flexibility over their finances if and when they need it."

Tesco, which offers an "open door policy" for suppliers who are worried they may run into problems, are also signing up to the Prompt Payment Scheme.