The retailer is believed to have signed on with MasterCard to promote its forthcoming petrol offer and a Fly Buys point’s scheme.

Coles, a prime mover in getting the Reserve Bank of Australia to overhaul credit card regulation, is believed to have chosen MasterCard over rival Visa for the co-branded card.

According to a document obtained by The Australian, prepared for advertising agencies, Coles has called for tenders asking agencies to prepare a launch plan for the card.

It is understood an agreement with MasterCard, operated by US group GE Capital, will be signed soon.

News about the imminent Coles/MasterCard move comes as the retailer prepares to unveil its fuel deal with Shell Australia.

A Coles spokesman said yesterday: "Fundamentally, our goal is a program that rewards customers, all customers, based on what they spend and not just on whether they own CML shares."

The decision to combine Fly Buys, which has about five million users, is likely to be well received by Coles shareholders who were disappointed by management's decision to phase out the expensive discount card.

The idea is that Coles-MasterCard users will be able to use the co-branded credit card to buy their groceries, qualify for a petrol discount and get the additional Fly Buys points from their petrol purchase.

Customers will also be able to use the card outside Coles Myer stores and overseas.

The existing Coles Myer card is the biggest in-store card in Australia, with over one million users.