Right now he can barely walk. But boy, can Casey Stoner ride.

The Honda star was almost one second faster than everybody else in a dominant and ominous display during Friday practice for the Australian Motorcycle Grand Prix at Phillip Island.

Just weeks after surgery on a serious ankle injury, Stoner was clearly the fastest man across both sessions - which bodes well for his shot at a sixth consecutive Australian GP win on Sunday.

In his farewell appearance on home soil before he retires from MotoGP at the end of the season, Stoner didn't let down a record Friday attendance of nearly 30,000.

In both sessions he put down quick early lap times.

And as his rivals closed in, he went even faster - the only man to break the 1min 30sec barrier for the day.

After the second session, Stoner was walking with a noticeable limp - clearly in discomfort as he rides through the pain barrier.

"I've been improving every day, but today helped me with some confidence," Stoner said.

"I've got to move on this track a lot less than (his comeback race) in Japan and Malaysia, so I've had a lot less issues with the ankle on the bike."

In changeable weather conditions, Stoner made his intentions clear with a fast early time, before light rain interrupted the first of the day's two 45-minute sessions.

After the rain cleared, Stoner again put down a sizzling marker - his 1:30.374 lap faster than world championship contenders Jorge Lorenzo (1:31.279) and Dani Pedrosa (1:31.533).

It was a similar story in the second period.

Stoner was quick early, then punched out another low number as his rivals appeared to be closing in on his pace.

He then went even quicker, with a head-shaking fastest lap of 1:29.999 - teammate Pedrosa next best and second fastest for the day with a 1:30.884 ahead of Lorenzo (1:31.005).

Yamaha rider Lorenzo leads fellow Spaniard Pedrosa by 23 points in the championship.

They are the only two riders who can win the crown with two races remaining.

Australian Kris McLaren, making his MotoGP debut as a replacement rider for the Avintia team, was slowest of the 20 riders in both sessions.

Qualifying will be held on Saturday ahead of Sunday's race.