A union that represents staff at the Dominick's unit of US grocer Safeway has accused the company of not acting in "good faith" in is attempts to sell the Chicago-based Dominick's supermarket chain.

The United Food and Commercial Workers Union (UFCW) has claimed Safeway did not consider a bid from private investment company Yucaipa Cos "on the same basis as other comparable and similarly qualified buyers," reported Reuters.

A spokesman for the UFCW said the union is "seeking an order through arbitration directing Safeway to open the sale process in good faith so that all potential buyers, including those who will agree to recognise the unions, will be treated fairly and the same as all other comparable and similarly qualified buyers."

A spokesman for Safeway said the retailer would respond to the union’s grievance but maintained that Safeway had "conducted a fair and an appropriate bidding process."

Safeway announced earlier this week that it has counter-sued Yucaipa over the Dominick’s sale process. To read more, click here.