Competition watchdogs were granted a six-day extension yesterday to deliver their verdict on which of four supermarket rivals should be allowed to bid for Safeway.

Trade and Industry Secretary Patricia Hewitt was due to receive the recommendations of the Competition Commission today.

The new deadline is next Monday, August 18.

In a statement, the Department of Trade and Industry (DTI) said the Commission had asked for an extension following a further meeting requested by one of the parties last week.

A DTI spokesman refused to confirm reports the unnamed group was Asda, the supermarket owned by US retail giant Wal-Mart, which is understood to have held talks with the Commission last week.

DTI minister Jacqui Smith said: "I have decided to give the Competition Commission a six-day extension to ensure that the views of all parties and the group on the issues that have been raised regarding these mergers are accurately reflected in the final report."

Once the report is handed over, the DTI is expected to take about six weeks to digest the watchdog's findings before announcing its decision - meaning a ruling is now unlikely before the end of September.

Newspaper reports have suggested that possible bids from Tesco, Sainsbury's and Asda would be blocked by the Government on competition grounds.

That would leave the way clear for William Morrison to make an offer for Safeway, the UK's fourth-biggest supermarket operator.

Morrison has argued its proposed takeover would create a fourth force in UK supermarkets.

The commission has been examining whether any of the proposed deals would create an excessively dominant supermarket group which would damage shoppers.

At the heart of the bids are local and national competition issues, prices and the impact of the potential mergers on suppliers.