Four-time Formula One world champion Sebastian Vettel has said he plans to go on the attack in Sunday's season-opening Australian Grand Prix, despite problems with his Red Bull car.

"We have been very successful in the last few years, but now things are a bit more difficult, we will start the season at a bit of a disadvantage," Vettel told broadcaster Servus TV.

"That means we have to fight, charge forward and take everything we can get."

Vettel endured a frustrating four days of testing in Bahrain 10 days ago due to electrical issues and problems with the car's new Renault engine.

Vettel said the problems were caused partly by the car's new drivetrain, the components which supply power to the wheels.

"It's down to the changes in the regulations. We have a completely new drivetrain that has given us a lot of worry so far," he said.

"It's very complex and we are having difficulties even to understand everything.

"When a small part doesn't fit properly, then the car just won't go."

Vettel predicts the introduction of new turbo engines will have a major impact on all teams, making the cars more unreliable and prone to breaking down, when the season starts in Melbourne.

"In the 90s and 80s, it was quite normal," said Vettel.

"We have seen there were problems in testing, not only for us.

"In races, that would just mean the cars stop and I estimate that only half of them will finish."

The 26-year-old German is bidding for a fifth consecutive world title, but fumed "just getting to the finish would be a success" in the wake of the Bahrain testing.

Williams' Felipe Massa posted the fastest time in Bahrain, clocking 1min 33.258secs, while Vettel came in 18th-fastest overall with Red Bull team-mate Daniel Ricciardo 10th.