His comments came after Asda announced reductions of unleaded and diesel to 109.9p and 121.9p per litrey.

Mr Givan commented: "I have been receiving complaints from local people who feel they are losing out in Lisburn when they compare prices to other parts of Northern Ireland.

"The policy of Tesco and Sainsbury is to set its prices based on local competition, which in essence means Lisburn Tesco and Sainsbury customers are paying more for fuel than customers in other parts of Northern Ireland where an Asda garage or any other garage cuts the cost of fuel.

"For example the Sainsbury garage in Coleraine is selling unleaded and diesel at 2p a litre cheaper than their garage in Lisburn because they are competing with Asda in Coleraine.

"This system by Tesco and Sainsbury of setting the prices locally is inherently unfair because the cost to them of buying the fuel for all their petrol stations is the same and therefore a universal price across Northern Ireland as used by Asda should be introduced. "

He continued: "At a time when everyone is feeling the pinch from the credit crunch and soaring food bills petrol stations such as Tesco and Sainsbury's in Lisburn should be passing on the full reductions they are benefiting from as the cost of wholesale prices for petrol and diesel continue to fall."

"Failure to pass on the reductions to customers in Lisburn, whilst doing so in other parts of Northern Ireland, is nothing less than exploitation."