TOKYO, Dec 14 (Reuters) - Japan's supreme court has ruled in support of Kansai Super Market Ltd's merger with H2O Retailing Corp, Kansai Super Market said on Tuesday, a decision that ends attempts by supermarket operator OK Corp to halt the move.

OK Corp, which was interested in buying Kansai Super Market, had sought an injunction over alleged irregularities with Kansai Super Market's vote-counting process at the shareholder meeting that approved its merger with H2O Retailing.

A district court initially granted an injunction that was subsequently overturned in a high court.

In a statement on Tuesday, OK Corp said it would not continue to pursue a takeover and would sell its stake back to Kansai Super Market.

"We believe that a just decision has been made on the matter," Kansai Super Market said in a statement on Tuesday announcing the supreme court decision.

The merger will take place as planned on Wednesday, the retailer said. (Reporting by Sakura Murakami; Editing by Clarence Fernandez and Christopher Cushing)