Formula One championship leader Nico Rosberg crashed in final practice for the Austrian Grand Prix on Saturday, leaving his Mercedes mechanics plenty of work to repair his car for qualifying.

The German is hoping to win the race at the scenic Red Bull Ring for the third year in a row on Sunday to increase his 24-point lead over team mate and triple champion Lewis Hamilton as the season nears the halfway point.

However the accident, after he had dominated Friday's practice sessions with the fastest lap at the circuit nestling in the wooded Styrian hills, dealt a setback to his  preparations.

Mercedes said they were investigating the cause of the crash, at the turn two hairpin, which appeared to be a rear suspension failure after he went over a kerb and spun several times.

The session was halted with 21 minutes remaining and the car brought back to the garage on a truck, with Rosberg making his frustration evident on his return.

Hamilton had earlier expressed concern about his car's rear tyres, asking the team over the radio to take a look because "something is not right."

"I'm going to go off if I keep on going," he said when asked to continue.

Ferrari's Sebastian Vettel, who will have a five-place grid penalty for an unscheduled gearbox change, lapped fastest in the session with team mate Kimi Raikkonen second on a bright morning with the threat of later rain.

Vettel's lap of one minute 07.098 was faster than Rosberg's Friday best. Hamilton, who struggled for pace in the first two sessions, was third in 1:07.308.

Australian Daniel Ricciardo was fourth fastest, ahead of Red Bull team mate Max Verstappen and the two Williams of Valtteri Bottas and Felipe Massa.