Casey Stoner topped the times in a rain-affected Saturday practice session for the Australian Grand Prix at Phillip Island, just edging out Dani Pedrosa for the top spot.

Stoner headed the times early in the session, but just over 20 minutes into the one-hour session Pedrosa went to the top of the times at the end of a run of quick lap times. Five minutes later, Stoner returned the favor to go back to the top of the times with a 1:30.626, 48 thousandths of a second faster than Pedrosa's effort.

And that was how it stayed, as rain in the second half of the session prevented fast times from any of the riders.

Championship leader Valentino Rossi was the only other rider close to Stoner and Pedrosa, about a quarter of a second behind them.

His teammate and championship rival Jorge Lorenzo was next fastest, but half a second slower than Rossi and eight-tenths slower than the session's fastest time.

Alex de Angelis was again best of the rest on his Gresini Honda, just over a second off the pace, with Mika Kallio next fastest on his Pramac Ducati, his teammate Niccolo Canepa not taking part after his heavy crash at Doohan corner in yesterday's session.

After a promising start to the weekend, both Tech 3 Yamaha riders struggled to set fast times today, James Toseland 2.2 seconds down in 12th while Colin Edwards ended the session nearly three seconds off Stoner in 16th and last position.

Pos  Rider             Bike             Time       Gap
 1.  Casey Stoner      Ducati           1m30.626s
 2.  Dani Pedrosa      Honda            1m30.674s  + 0.048s
 3.  Valentino Rossi   Yamaha           1m30.901s  + 0.275s
 4.  Jorge Lorenzo     Yamaha           1m31.427s  + 0.801s
 5.  Alex de Angelis   Gresini Honda    1m31.707s  + 1.081s
 6.  Mika Kallio       Prama Ducati     1m31.969s  + 1.343s
 7.  Andrea Dovizioso  Honda            1m32.176s  + 1.550s
 8.  Toni Elias        Gresini Honda    1m32.185s  + 1.559s
 9.  Marco Melandri    Hayate Kawasaki  1m32.303s  + 1.677s
10.  Nicky Hayden      Ducati           1m32.403s  + 1.777s
11.  Loris Capirossi   Suzuki           1m32.443s  + 1.817s
12.  James Toseland    Tech 3 Yamaha    1m32.905s  + 2.279s
13.  Chris Vermeulen   Suzuki           1m33.017s  + 2.391s
14.  Randy de Puniet   LCR Honda        1m33.261s  + 2.635s
15.  Gabor Talmacsi    Scot Honda       1m33.471s  + 2.845s
16.  Colin Edwards     Tech 3 Yamaha    1m33.591s  + 2.965s