ONGOING NEGOTIATIONS: Mercedes driver Nico Rosberg wants a new deal of three years, but the team is only wants to offer his one. Image: AP / Claude Paris

Canada - The first sign of trouble in Nico Rosberg's negotiations with Mercedes has emerged.

Earlier, both the German outfit and the 2016 championship leader have indicated they are likely to continue working together beyond the expiry of Rosberg's contract this year.

Money not the issue

It was thought any wrangling would be about Rosberg simply upping the value of his retainer, but Gerhard Berger said: "It's not about money. It's about something else."

Berger, the former F1 driver and BMW and Toro Rosso chief, has been brought in by Rosberg and his father Keke to handle the negotiations with Mercedes.

Germany's Bild newspaper claims the uncertainty about a new deal for Rosberg is indeed less about money and more to do with whether Mercedes wants to promote its young charger Pascal Wehrlein from Manor.

READ: Mercedes head-honcho - 'Wehrlein is our F1 future'

The team might therefore be happy with a mere one-year deal for Rosberg next year, but Berger and the 30-year-old is pushing for a full three-year extension.

Berger said: "We need to agree with the strategy that they (Mercedes) want to go with for the future. If they agree, then we can negotiate."