Mercedes must keep Rosberg - Lauda

May 27 (GMM) Niki Lauda on Friday said it must be Mercedes' priority to keep Nico Rosberg.

Championship leader Rosberg's contract expires at the end of the year, and he is being assisted in his negotiations to renew it by F1 legend Gerhard Berger.

"I'm friends with him and his father Keke," Berger confirmed to Bild newspaper.

"He (Nico) wants to be able to concentrate on driving and the world championship."

Lauda, who is Mercedes' team chairman, commented: "So now two Austrians (Lauda and Berger) negotiate over a German-Finn."

Undoubtedly, Berger is pushing for more money for Rosberg, given his run of winning form recently and the face teammate Lewis Hamilton earns significantly more.

But another negotiating point will be the timing of the contract.

One year is too short and three years too long, and the prospect of a two-year deal would mean Hamilton and Rosberg's deals would expire at the same time -- something a top team wants to avoid.

Lauda, though, said: "For me it's no problem if both contracts expire at the same time.

"Then we'd negotiate with one in March and the other in April. The aim must be to keep Rosberg," he told Auto Motor und Sport.

Meanwhile, it emerges that Lauda's own contract as Mercedes team chairman expires at the end of 2017.

Recently, when asked if he wanted to buy back control of his former airline, the triple world champion told Kleine Zeitung newspaper: "Definitely not.

"I have a job to do at Mercedes for almost two more years, which would be incompatible (with that)."