Formula 1: Hamilton fastest in Australian Grand Prix first practice

The Mercedes F1 driver headed team-mate Valtteri Bottas by more than half a second, as Red Bull edged Ferrari to be best-of-the rest.

Sebastian Vettel was the first car to hit the Melbourne track as he led the initial burst of installation runs, but it took 20 minutes for anyone to set a time.

The first flying lap came from Williams rookie Sergey Sirotkin, but his 1m32.057s did not stand as the benchmark for long.

Within five minutes the big teams began to make their mark, with Kimi Raikkonen and Valtteri Bottas briefly going quickest before the Red Bulls hit the front.

Max Verstappen twice grabbed top spot from team-mate Daniel Ricciardo - interrupted by Hamilton's first spell atop the times - and Verstappen was the first driver to dip below the 1m25s mark, on a 1m24.959s.

Hamilton stamped his authority on the session not long after the half-hour mark, first lapping 0.022s quicker than Verstappen and then improving to 1m24.531s.

After a mid-session lull in activity, Bottas emerged on a new set of ultrasofts and lapped 0.046s slower than Hamilton, but the four-time champion hit back with a 1m24.026s to go half a second clear.

Bottas could not get any closer to Hamilton over the rest of the session, and although Verstappen improved his time after switching to supersofts, third and 0.745s off the pace was the best Red Bull could manage.

Ferrari split the two Red Bulls and occupied fourth and fifth place, with Raikkonen using soft tyres to lap a tenth quicker than Vettel, who made a mistake on his first flying lap on supersofts but improved on his second.

Ricciardo ended the session sixth-fastest, a quarter of a second behind Verstappen but comfortably clear of an ultra-tight midfield headed by Romain Grosjean.

Haas looked strong in pre-season testing and Grosjean continued that form in Australia, as a second covered the Frenchman in seventh to Sergio Perez's Force India in 16th.

Fernando Alonso ended up slightly slower than Grosjean after McLaren recovered from a difficult start to FP1 to end up with both cars in the top 10.

Alonso and Stoffel Vandoorne spent most of the first hour in the garage. Alonso suffered an exhaust problem, while Vandoorne was largely absent save for a run that featured a "driveability" issue.

When Alonso emerged for proper running in the final half hour he made quick progress up the order and eventually settled into eighth with a 1m25.896s best set on supersofts, but he would have been faster without a scruffy final sector.

Vandoorne used soft tyres to rise to 10th, half a second behind Alonso, as Carlos Sainz Jr's supersoft-shod Renault split the MCL33s.

Pierre Gasly's Toro Rosso-Honda was 11th quickest, only fractionally slower than Vandoorne's McLaren-Renault.