Australian retailer Coles' tactic to delay a decision on the sale of its business has drawn out more bidders and sent offers rolling towards the A$20bn (€12.3bn) mark in a move that could yet boost the size of the nation's largest buyout.

Coles, Australia's second largest retailer, rejected Wesfarmers offer over the weekend of A$19.7bn as three more bidders joined the race for the retailer chain.