Jenson Button got McLaren's season off to the perfect start as he led a 1-2 at a damp Albert Park circuit on Friday.
The 2012 season received the green light at noon on Friday with the track declared wet after a few showers earlier in the day.
This, though, did little to dampen spirits as a massive crowd was present for the opening day of the season.
Button took the honours with a 1:27.560, dethroning Mercedes's Michael Schumacher late in the session.
His team-mate Lewis Hamilton followed suit minutes later as, in the dying seconds of practice, he climbed to second place just 0.245s off the pace.
The McLaren duo relegated Schumacher to third, 0.675s off the pace.
Fernando Alonso, who had a near miss as the chequered flag fall when he went into a slide through the final corner almost hitting the pit wall, was fourth quickest ahead of Mark Webber and Nico Rosberg.
It was a solid start to the season for Toro Rosso and Williams with Daniel Ricciardo and Pastor Maldonado seventh and eighth while Kimi Raikkonen was ninth.
However, the Lotus F1 racer had a very slow start to his season as he was stuck in the pits for most of the session with a steering column problem. He managed just eight laps.
Kamui Kobayashi completed the top ten ahead of reigning World Champ Sebastian Vettel.
It was a disappointing start to the season for Felipe Massa, who lost control of his F2012 under braking for Turn 9, beaching his car in the gravel.
But it was an even worse start for HRT who were not able to get Pedro de la Rosa out onto the track at all while Narain Karthikeyan's practice ended after three laps with an engine problem.
01. Jenson Button McLaren-Mercedes 1:27.560 11 laps
02. Lewis Hamilton McLaren-Mercedes 1:27.805 + 0.245 14 laps
03. Michael Schumacher Mercedes 1:28.235 + 0.675 17 laps
04. Fernando Alonso Ferrari 1:28.360 + 0.800 21 laps
05. Mark Webber Red Bull-Renault 1:28.467 + 0.907 21 laps
06. Nico Rosberg Mercedes 1:28.683 + 1.123 22 laps
07. Daniel Ricciardo Toro Rosso-Ferrari 1:28.908 + 1.348 23 laps
08. Pastor Maldonado Williams-Renault 1:29.415 + 1.855 16 laps
09. Kimi Raikkonen Lotus-Renault 1:29.565 + 2.005 8 laps
10. Kamui Kobayashi Sauber-Ferrari 1:29.722 + 2.162 26 laps
11. Sebastian Vettel Red Bull-Renault 1:29.790 + 2.230 21 laps
12. Nico Hulkenberg Force India-Mercedes 1:29.865 + 2.305 17 laps
13. Paul di Resta Force India-Mercedes 1:29.881 + 2.321 18 laps
14. Bruno Senna Williams-Renault 1:29.953 + 2.393 21 laps
15. Sergio Perez Sauber-Ferrari 1:30.124 + 2.564 22 laps
16. Romain Grosjean Lotus-Renault 1:30.515 + 2.955 16 laps
17. Heikki Kovalainen Caterham-Renault 1:30.586 + 3.026 16 laps
18. Felipe Massa Ferrari 1:30.743 + 3.183 11 laps
19. Jean-Eric Vergne Toro Rosso-Ferrari 1:31.178 + 3.618 17 laps
20. Vitaly Petrov Caterham-Renault 1:31.983 + 4.423 8 laps
21. Timo Glock Marussia-Cosworth 1:34.730 + 7.170 8 laps
22. Charles Pic Marussia-Cosworth 1:40.256 + 12.696 11 laps
23. Narain Karthikeyan HRT-Cosworth no time 3 laps
24. Pedro de la Rosa HRT-Cosworth no time