The independent MP was struck outside her office in Wangaratta, Victoria, on Monday afternoon.
The driver has been arrested. According to Prime Minister Anthony Albanese, the man made a U-turn after initially driving past Helen Haines.
"It's clear that it was a deliberate attack. It was not an accident," Albanese told ABC, adding that the motive remains unclear.
Wangaratta is about 200 kilometres northeast of Melbourne, on the main road to Sydney.