Morrisons was due to talk to the Office of Fair Trading today as the battle for Safeway heats up.

The Bradford store chain - whose shares opened up 0.5p at 179.5p today - will tell the OFT that the merger would create a strong fourth national retailer "capable of offering a sustained value-based price challenge, particularly to Tesco and Sainsbury's in London and the South and to Asda in Scotland".

The firm will also argue that the move would be best for customers, as it would add more competition.

Morrisons said it would keep its uniform pricing policies for all stores, except the smaller convenience stores which will continue to trade as Safeway. It will also tell the OFT that prices will fall for consumers as it will bring in its national pricing policy to Safeway stores.

Morrisons also said the merger between it and Safeway would not create geographical problems. It has found only seven locations, out of 598 combined store locations, where stores may have to be sold to satisfy competition concerns.

Morrisons said smaller suppliers were likely to see higher sales from the merged group.

The firm also argued that the 135,000 people it would employ as a result of the merger would benefit.

Sir Ken Morrison, chairman of Morrisons, said: "We have laid out our case for merging with Safeway clearly and in some detail. We believe our arguments are compelling, naturally the OFT will make its own judgement once it has taken all views into account. We strongly believe that four national food retailers is better for competition than three. Morrisons and Safeway have little overlap."

Since Morrisons tabled the £2.9 billion Safeway offer, which has since fallen to £2.5 billion, Sainsbury's and Asda have shown interest in the bid.

Wal-Mart, which bought Asda in 1999, has asked the OFT for competition clearance to bid for Safeway.

It said its offer would "emerge" if it got the green light to make a deal.

Both Sainsbury's and Wal-Mart would probably have to sell dozens of stores to satisfy the OFT, which could refer the takeover battle to Patricia Hewitt, trade and industry secretary.