German retailers Edeka and Tengelmann have been given a further three weeks to allay concerns that the merger of their discount businesses could hit competition in the country.

Germany's Federal Cartel Office has pushed back the deadline for its decision on whether to approve the companies' move to combine their Netto and Plus businesses.

A spokesman for the Bundeskartellamt said the deadline had been extended from 28 April to 16 May.

"In roughly 100 local markets, we found a strengthening of Edeka's market position," the spokesman told just-food. "The companies will have to come up with some solutions to clear up these problems."

Under a deal struck in November, Edeka will take a 70% stake in a venture that will run its Netto discount outlets and Tengelmann's Plus stores.

The venture will operate around 4,200 stores in total, generating annual sales of about EUR11bn (US$17.5bn).

Tengelmann, which will hold a 30% stake in its venture with Edeka, has been searching for a partner to breathe new life into its 2,900 Plus stores in Germany.

Officials at Edeka and Tengelmann could not be reached for immediate comment.