German grocery retailer Rewe has said its chief executive Hans Reischl is to leave the company eight months earlier than planned.

Reischl, who has been chief executive of the group since 1980, is believed to be leaving earlier than expected because of a row over his new role at rival KarstadtQuelle, reported the Financial Times.

Reischl is expected to take up a position on the supervisory board of KarstadtQuelle, which has agreed to set up a joint venture with Rewe regarding food counters in its department stores.

Reischl’s move is believed to have caused concern among Rewe board members about a possible conflict of interest, the newspaper reported.

Rewe said Ernst Berninghaus, who was due to take over from Reischl at the end of the year, is to become CEO at the end of this week. Berninghaus is currently a member of Rewe’s board and is responsible for the company’s international business.