Breaking: Police not ruling out further serious charges over Helen Haines attack

Police Commissioner Mike Bush says they haven't ruled out laying further charges against Brendan Nugent. (ABC News)

Further serious charges may be laid against a Victorian man over his alleged attack on Indi MP Helen Haines on Monday.

Brendan Nugent, 43, has been charged with dangerous driving causing serious injury, intentionally causing serious injury and causing harm to a Commonwealth public official.

Ms Haines, 65, remains in hospital in a critical but stable condition.

Victorian Police and the Australian Federal Police (AFP) told a press conference this morning they have not ruled out laying further charges, including attempted murder.

"While I say this investigation is far from complete, we are not ruling out further serious charges," Victorian Police Chief Commissioner Mike Bush said.

"I want to further add that we have deployed a number of staff into Wangaratta to give assurance to members of the public.

"We do believe this was a deliberate but isolated act."

AFP Commissioner Krissy Barrett said authorities had been seeing an increase in unlawful behaviour towards parliamentarians, with "almost one individual every week" charged for targeting Commonwealth officials.

"I hope that this terrible event — that will forever change the life of the member for Indi and her family — gives our country time to pause and reflect on the growing threats and unlawful behaviour against those who hold a Commonwealth office in Australia," she said.