Mercedes' Lewis Hamilton will start the Bahrain Grand Prix with a five-place grid penalty for breaching rules over gearbox changes.
Governing body the FIA's rules state drivers cannot change gearboxes within a six-race period.
The defending champion needs a new gearbox for Bahrain after problems in the opening race, his team said.
"We had an hydraulic leak in the Melbourne race and were fortunate to finish the race," Mercedes said.
"Unfortunately we couldn't repair it within the six-race cycle."
Hamilton finished second in Melbourne, behind Sebastian Vettel. The Bahrain Grand Prix, the second race of the F1 season, takes place on Sunday, with final practice on Saturday from 13:00 BST.