Saturday's qualifying sessions for the Australian MotoGP have been postponed until Sunday, with the windswept Phillip Island circuit deemed unsafe by riders.

Fourth practice was red-flagged soon after Miguel Oliveira suffered a scary high-speed crash on his Red Bull KTM Tech 3.

As the Portuguese rider was taken to the medical centre, a safety commission meeting was convened and the 21 remaining riders voted to abandon racing for the rest of the day.

MORE TO COME

- AAP