Discount vouchers and in-store loyalty promotions have been criticised by the Director of Consumer Affairs for obscuring prices and making it more difficult for shoppers to tell whether they are getting good value for money.

Addressing the Londis Topshop retailer conference in Druid's Glen, Co Wicklow, Ms Carmel Foley said competition, not special offers, was the best way of keeping prices low and delivering customer value.

Ms Foley suggested that discounting may put retailers in breach of the prohibition on below-cost selling.

She also had stern words for the convenience retail sector, which she said was reaping "super-profits" thanks to generous mark-ups.

She called on the industry to explain why its prices were frequently higher than those of the major multiples.

Also speaking at the conference, the Tánaiste, Ms Harney, said the growth of the convenience sector was bringing increased choice to consumers.

Mr Simon Healy, executive director of Londis Topshop, told delegates that the recent acquisition of Londis Topshop by ADM Londis from its joint venture partner, Tedcastle Holdings, would deliver greater efficiencies and improved bargaining power.

Ms Ailish Forde, director general of RGDATA, the small grocer lobby, said that, despite increased competition following the entry of foreign players into the retail market, local stores were still a force to be reckoned with.

She added: "In the current economic climate, the grocery market has never been as challenging. The strength of local shops for local people must never be underestimated."

Londis and Londis Topshop employ about 4,000 people in 260 stores around the State.