11/09/2016 8:01 AM AEST | Updated 12/09/2016 6:03 AM AEST

Man Charged With Sydney Stabbing 'Inspired By ISIS': Police

The 22-year-old has been detained by counter terrorism police.

Supplied via Fairfax
Police are investigating after a man was stabbed in Minto.

A 22-year-old man charged with committing a terrorist act and attempted murder after allegedly stabbing a man in Sydney's southwest was inspired by Islamic State.

The horrific incident took place on Ohlfsen Road in Minto on Saturday afternoon when 59-year-old Wayne Greenhalgh was walking his dog when he was stabbed multiple times.

Facebook / Fairfax Media
Wayne Greenhalgh was stabbed in suburban Minto.

Greenhalgh was treated at the scene by ambulance paramedics before being taken by helicopter to Liverpool Hospital suffering serious injuries.

The Sydney Morning Herald reported he had a punctured lung and other deep lacerations, needing more than six hours of surgery on Saturday night.

Later on Saturday, officers from Macquarie Fields LAC arrested a man, 22, in the Minto area. When police approached him he allegedly tried to stab an officer and had to be subdued with a taser.

The man was subsequently charged with committing a terrorist attack and attempted murder by the Joint Counter Terrorism Team.

The acused man has been named in media as Ihsas Khan. He was formally refused bail on Sunday and the case was adjourned to Wednesday.

Speaking on Sunday, NSW Police Force Deputy Commissioner Catherine Burn said authorities believed the alleged assailant was inspired by Islamic State.

"We will be alleging before the court that this was an act that was inspired by ISIS," Burn told reporters in Sydney.

"We know that this person has strong extremist beliefs inspired by ISIS.

"What made him actually act yesterday, we don't know. But hopefully, our further investigations will uncover that. It was deliberate. It was violent."

She described the attack as "the new face" of terrorism, saying the alleged assailant was known to police but that he was not believed to be directly connected to known terror groups.

Burn said local police knew that the man "had some problems" but that he had not been "front and centre" of authorities' work.

She said there appeared to be a degree of planning in the attack and that the situation could have been much worse.

The attacker did not know the victim but had formed a view about him, she said.

Police earlier said they seized a large knife for forensic examination.

Network Seven reported that the charged man is well known in the local community for his extreme religious views.

It has also been reported that Witnesses heard the 22-year-old man shouting in Arabic during and after the attack.

In a statement, police moved to calm fears of more attacks, saying there was no "ongoing threat in relation to this incident".

On Sunday afternoon, Attorney-General George Brandis paid tribute to bystanders who helped the stabbed man.

Brandis said he wanted to "thank members of the community who as bystanders returned ... to assist the victim of the attack".

"They acted heroically and we should all be in their debt," he told reporters in Brisbane.

Brandis confirmed that the accused knifeman was known to authorities.

He also said 2 pieces of anti-terror legislation would be introduced into parliament this week to toughen up existing laws on control orders and post sentence detention.