"We are already sitting together and negotiating with Lewis Hamilton. About a multi-year contract, even," he revealed.
Wolff said Mercedes is more than happy with its current driver lineup of German Rosberg alongside Briton Hamilton.
"Lewis is a fixed part of the team," he said, "and I would hope for a long time to come."
For the moment, however, Hamilton is keeping a low profile on the subject. There are paddock rumours he might be tempted to return to McLaren, particularly if Rosberg goes on to win the number '1' for his 2015 car.
"My contract ends in a year," said Hamilton, "so I have time. I'm not thinking a great deal about it."
But even Rosberg seems happy for Hamilton to stay, even though they have clashed off the track this year as they fight for the drivers' title.
"I see no reason why it can't work as it has in the long term," he told Germany's Bild am Sonntag newspaper ahead of the German grand prix.
"We have difficult moments but then we discuss them together and move on."