Formula One world champion Lewis Hamilton is close to finalising a new deal with Mercedes, team principal Toto Wolff said.

The Brit, 33, has reportedly been nearing a new deal with the team for several weeks, but the parties are yet to finalise terms.

However, Wolff said on Friday that he expected a deal to be done, with the last details being finalised.

"We have been discussing before going into the winter holiday and then we kind of left it there to get away from Formula One and picked it up again in January," he told a news conference at the Australian Grand Prix.

"These discussions are going in the right way. We are about to finalise the last topics and there is no reason to not think that's going to happen soon.

"He's in a good frame of mind. I've seen him come back strong from the winter."

Hamilton is a four-time world champion, trailing only Michael Schumacher (seven) and Juan Manuel Fangio (five) for the most titles.

He showed good signs in the opening session of the 2018 season, topping first practice in Melbourne.

Hamilton's time of one minute, 24.026 seconds was 0.551secs quicker than his Mercedes team-mate Valtteri Bottas.

Red Bull's Max Verstappen and Ferrari duo Kimi Raikkonen and Sebastian Vettel completed the top five.