Shares in Australia's second-largest supermarket operator Coles Myer have risen as a result of renewed speculation that Wal-Mart is preparing a bid for the company.

Australian reports have suggested that the world's largest retailer has sent a delegation to Melbourne, hearsay that Wal-Mart has declined to comment on.

However, Wal-Mart did confirm that it is considering various options for expansion into new markets. "We are constantly looking at options to expand internationally. This can be achieved through organic growth and bolt-on acquisitions," a spokesperson told just-food.

The Coles board recently rejected a buyout proposal from an American-led consortium bidding to acquire the company for a price of A$14.50 (US$11.13) per share, stating that it undervalued the company.

Coles shares closed up four cents at A$14.44.