Superquinn's 4,500 staff are likely to demand a share of the €450 million being paid by a group of investors for the company.

Mandate, the union representing 90 per cent of the supermarket chain's staff, says workers have made a major contribution to the company's success and are entitled to a share of the benefits.

It is to hold a meeting of shop stewards in the company on Thursday to discuss the issue and other implications of the takeover.

Mr John Douglas, general secretary-designate, said the union was informed of the buyout on Saturday at a meeting with the company, attended by Mr Simon Burke, who is to be the new executive chairman.

He said initial guarantees had been given regarding the terms of employment and job security of the supermarket chain's staff.

There had been no discussion at that stage about the prospect of a monetary reward for staff arising from the takeover.

Mr Douglas said there were precedents for such payouts, however, and he believed Superquinn's staff were entitled to a "goodwill gesture" payment.

Superquinn, he said, had always placed a strong emphasis on the quality of its customer relations, and it was through the staff it had achieved success in this area. "They should be rewarded in relation to the sale of the company. They have increased the value of the company by their efforts." This was a matter for the existing management, rather than the new owners, to address, Mr Douglas said.

A similar goodwill payment was sought by 8,500 workers at Quinnsworth and Crazy Prices when those chains were taken over by Tesco in 1997.

Tesco refused and a strike was threatened, before unions opted instead to negotiate long-term improvements in pay and conditions.