Independent federal MP Helen Haines has lost one leg after she was struck by a Land Cruiser and pinned between two cars in what the prime minister said was a “deliberate” attack.

The ABC reported that surgeons were fighting to save her second leg.

Haines underwent emergency surgery overnight and was in a stable condition on Tuesday, fighting for her life in hospital.

Haines, 65, was reportedly hit twice while retrieving something from the boot of her car outside her electorate office in Wangaratta, Victoria, on Monday at about 3.35pm.

The Land Cruiser made a U-turn, hit her, reversed and hit her again, according to government ministers.

“What witnesses have described is the driver doing a U-turn to get into the car park and to ram Helen against a vehicle, then to reverse and do it a second time,” Home Affairs Minister Tony Burke told ABC Radio on Tuesday.

“A bystander ran towards the scene, got the driver out of the vehicle and held the driver until police arrived.”

The male driver who was arrested over the incident has been named as Brendan Nugent, age 43.

Nugent, who is from the nearby town of Tarrawingee, is in custody after heroic local barber Ricky Jeffries performed a citizen’s arrest.

Australian Federal Police said he could be charged with causing harm to a Commonwealth public official.

If found guilty, he could face a maximum of 10 years’ imprisonment.

Multiple media outlets described Nugent as an environmental activist with a background in forestry.

Neighbours told the Melbourne Age they had complained to police about his behaviour this year, including playing loud music all night.

Haines, the independent member for Indi, was airlifted to a hospital in Melbourne, where she underwent surgery overnight, but remains in critical condition.

Victoria Police Acting Superintendent Ashley Mason said on Tuesday there was no evidence the man was previously known to law enforcement.

“There’s certainly no recent intelligence that I’m aware of that put him on our radar,” he told ABC News.

The man was to be questioned by investigators later on Tuesday morning after he was held at Wangaratta police station overnight.

Major crimes officers had travelled from Melbourne to the northern Victorian town to examine the crime scene, Mason said, adding the investigation would zero in on potential political motivation for the attack.

The incident is being investigated by Victoria Police’s counterterrorism taskforce in conjunction with spy agency ASIO and the Australian Federal Police, with the prime minister saying he will be briefed later on Tuesday.

Authorities are yet to determine the suspect’s motive or establish whether he is known to Haines.

Dr Helen Haines, pictured with husband Phil. Photo: Instagram

Ricky Jeffries was working at his nearby barber shop when he saw the incident and stepped in to apprehend the driver.

Jeffries told reporters on Tuesday he saw the alleged offender with a knife.

”He didn’t pull it out,” he said.

“I just wasn’t comfortable with his movements and so I basically just took it out of his pocket and threw it away.”

Federal leaders have labelled Jeffries a hero, but the barber insisted he was just one of many people playing their role as the emergency unfolded.

”I just was a person who had an opportunity to intervene in a safe-ish sort of way,” he said.

Threats of violence ‘through the roof’

On Tuesday morning, Parliament House was awash with reflections on Haines and her work, including her gentleness toward security guards and ordering of dozens of piccolo coffees from the internal cafe for her staff.

Following the apparent attack, several high-profile female politicians have also warned that threats of serious violence are becoming increasingly common.

“The threats of violence have gone through the roof in the time I’ve been there,” said Social Services Minister Tanya Plibersek, who entered parliament in 1998.

“Rape and death threats are regular.”

In the last year, reports of harassment towards Australian politicians rose from 951 to 1067.

Attacks on electorate offices have also grown.

Plibersek and her colleagues, including independent MPs Sophie Scamps and Monique Ryan, spoke with emotion as they recounted the popularity of the regional Victorian MP.

All of them stressed the importance of politicians staying accessible to the public, even as poor treatment towards them rose.

“This is the worst possible thing to happen to the best possible person in the world,” Ryan told ABC Radio.

“Helen is extraordinary and I wouldn’t say that if I didn’t mean it.”

Scamps, who called Dr Haines a “strong advocate for democracy”, said it was an attack on the core of Australian politics.

“There’s times during pre-election or the election campaigns where I think hatred and division is stoked purposefully, and I’ve had people being incredibly aggressive to me,” the northern Sydney MP said.

“I really hope that we don’t, you know, feel unsafe in our communities.”

Helen Haines with fellow rural independents Bob Katter, Rebekha Sharkie and Andrew Gee. Photo: Mike Bowers

Haines was praised by the Centre for Public Integrity, with which she has worked closely.

“She is passionate, principled, intelligent, warm and down to earth,” the centre said in a statement.

“We are shocked by the increasingly hostile environment in which Australian parliamentarians are working.

“Our democracy depends on people being willing and able to serve their communities, engage openly with the public and advocate for what they believe in, without fear for their personal safety.”

The sentiment was echoed by Climate200, the Simon Holmes a Court-led organisation that backed Dr Haines and other independents in the last two elections.

“There is no place for violence in politics,” the organisation said.

–with AAP