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 on Tuesday.

"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.

The 26-year-old German is bidding for a fifth consecutive world title.