United are being investigated by the Office of Fair Trading

The company said it had bought 6,500 shirts on the "grey" market in Europe because it could not obtain them through official channels.

The short-sleeved shirts will be sold in the firm's stores from Saturday for �24.86.

This compares to the �39.99 charged by the club's official Megastore.

The Premiership champions are among 10 firms being investigated by the Office of Fair Trading (OFT) over alleged price fixing of replica kits.

At last we're starting to see the whistle blown on rip-off football shirt prices Paul Crier, Asda

Phil Evans, principal policy adviser, of the Consumers' Association, said he welcomed Asda's move.

He added: "The decision by Asda to side-step Old Trafford on the price of Man Utd shirts is a great kick-off to the new season for many fans.

"Hopefully it will not just be Man Utd fans that benefit from this greater price competition and other Premiership fans will also find the price of their team's strips relegated to a more realistic price."

Asda struck a deal with Leeds United in 2002 to sell the club's shirts and is also in negotiations with Aston Villa and Southampton.

Paul Crier, Asda's general manager for sports goods, said: "At last we're starting to see the whistle blown on rip-off football shirt prices."

Manchester United refused to comment.

Nike said in a statement: "Nike does not control or set retail prices on any of our products, this is the responsibility of the retailer."