WANGARATTA: Australian independent lawmaker Helen Haines underwent surgery overnight but remains in a critical condition after being deliberately struck by a car, Prime Minister Anthony Albanese said on Tuesday.

Political violence is rare in Australia, but law enforcement agencies have documented a steady rise in threats and abuse directed at the nation's elected officials in recent years.

Albanese said the attack was a "test of our character" and prompted an outpouring of support for Haines, who has been widely praised for her efforts to increase transparency in politics and crack down on corruption.

She was hit by a Toyota Land Cruiser outside her office in the town of Wangaratta, just over 200km northeast of Melbourne, at around 3.35pm (0435 GMT) on Monday.