South Korea's antitrust regulator said Tuesday it has decided to approve a deal by Korea Seven Co., the operator of 7-Eleven convenience stores, to buy its smaller rival Ministop Korea Co.

In January, the country's retail giant Lotte inked a deal to acquire a 100 percent stake in Ministop Korea for 313.3 billion won ($257 million). Korea Seven, an affiliate of Lotte, eventually bought Ministop Korea.

The Fair Trade Commission (FTC) said it has given the green light to the deal, saying that the takeover is not expected to hamper market competition.

South Korea's convenience store market has been dominated by BGF Retail's CU and GS Group's GS25, with 7-Eleven, Shinsegae Group's Emart 24 and Ministop being minor players.

The FTC said its approval is expected to spur three-way competition in the market as the takeover will help Korea Seven cement its market status as the No. 3 player.

Korea Seven operates around 11,170 convenience stores across the country.

Ministop is an affiliate of the Japanese retail group Aeon Group and opened its Korean operation in 1990 via a business tie-up with South Korea's leading food maker Daesang. Ministop Korea runs around 2,600 convenience stores. (Yonhap)