Irish competition authorities are taking Tesco and Dunnes to court over alleged breaches of a ban on below-cost selling.

Investigators at the office of the director of consumer affairs in Dublin have scrutinised invoices from both retailers after complaints that recent promotions on babyfood sold the goods at below-cost price. The practice is banned in the Irish Republic under the Groceries Order.

A spokesman at the office of consumer affairs director Carmel Foley said both retailers would be prosecuted. The case is likely to be heard at a district court in January. Tesco Ireland and Dunnes declined to comment.

Independent retailers’ lobby group RGDATA welcomed the move. Director general Ailish Forde said: “It is vital groups with such incredible market power are not allowed to abuse it at the expense of consumers, suppliers and retailers.”