The German Federal Cartel Office has warned that it could move to block the merger of Edeka's Netto discount supermarkets with Tenegelmann's Plus stores.

"Edeka would have a dominant market position following the merger," the regulator said in a statement.

Edeka is the market leader in Germany's food retail industry, holding a 25% market share, the regulator said. The country's six biggest food retailers control about 90% of the market.

"We have been contacted by the Federal Cartel Office and they have requested that we make a statement in favour of the merger before a final decision is made. We will be doing this and believe that the merger would not limit competition in the retail market," a spokesperson for Edeka told just-food.

Edeka and Tengelmann revealed their plans to merge their discount chains last year.

The newly formed joint venture, in which Edeka would hold 70%, would operate 4,100 stores.