Tesco bought the two Czech chains with a total of 129 stores in December last year for 1 billion crowns ($56.95 million), pending approval by the Czech watchdog UOHS.

"There will not be a significant strengthening of the position of the Tesco group as a consequence of the merger on any ... level," the office said.

"Moreover, on all these levels there is strong competition including supermarket chains such as Ahold, (German-based) Schwarz and Rewe."

Penta sold the Polish part of the Zabka chain, one of Poland's largest retail chains, to regional rival Mid Europa Partners for about 400 million euros ($553.4 million) in late February.