The Slovakian PMU competition authority has blocked a deal between the UK's Tesco and France's Carrefour that would see Tesco acquire four hypermarkets in Slovakia.

The agreement originally allowed Carrefour to acquire six existing hypermarkets and two planned hypermarkets in Taiwan from Tesco and in return the UK grocer would have received 11 hypermarkets in the Czech Republic and four outlets in Slovakia.

The PMU said that it objected to the transaction because it would strengthen Tesco's dominant position in the market, and could potentially allow the supermarket group to act independently in its dealings with suppliers, consumers and rivals.

In order to appeal the decision, Tesco must raise objections within two weeks. The company declined to comment on whether it would do so.