Reigning Formula One champion Lewis Hamilton has topped both opening practice sessions at the Australian Grand Prix.

Local hope Daniel Ricciardo turned in encouraging displays on Friday at Albert Park in Melbourne, clocking the third-fastest time in the first practice and being fourth quickest in the second.

Mercedes star Hamilton justified his hot favouritism for the season-opening grand prix with the quickest laps in both sessions which were marred by wet conditions.

Hamilton, seeking a third consecutive world title, was almost half-a-second faster than his nearest rival in both sessions.

The Englishman clocked a best lap of 1min30.875sec in the first session but was almost eight seconds slower in the later practice as a wet track hampered drivers.

His teammate Nico Rosberg crashed out of the last session when he lost control and skidded into a wall, damaging the front wing and nose of his Mercedes.

Australian Ricciardo also found trouble with his opening practice session abruptly ending when he slid off the track and his car came to a halt in the sand.

Ricciardo left his car and walked back to the pits – stopping to allow some spectators to take his photo and shaking the hands of other fans on the way.

Despite that setback, Ricciardo had earlier managed to bank the third-fastest time in the initial session behind pacesetter Hamilton and Red Bull Racing’s Daniil Kvyat.

The West Australian also performed strongly in the second session, logging the fourth-best time behind Hamilton, Force India’s Nico Hulkenberg and Ferrari’s Kimi Raikkonen.