Children of man stabbed in 'lone wolf terror attack' in Sydney pay tribute to his rescuers

The children of the man attacked by a suspected lone wolf terrorist in Sydney have thanked the family who saved his life.

Wayne Greenhalgh, 59, was stabbed several times while walking through a reserve in Minto, around 4pm on Saturday.

His daughter, Lisa Ballard, said her father would have done the same for the family that intercepted a knife wielding student, charged with a terrorist act over the stabbing in the city's west.

"He went out of his way for anyone, whether it be picking up groceries for an elderly person, whether it be giving the shirt of his back," Ms Ballard said.

"The bravery I can’t even imagine but I can assure you if it was the other way around dad would do the same for any one of them."

Police said Ihsas Khan, 22, was inspired by Islamic State before the attack.

Investigators returned to the student's home on Monday to try to piece together his life before he attacked Mr Greenhalgh.

The victim suffered injuries to his body and hands and was treated by paramedics and flown by helicopter to Liverpool Hospital, where his condition on Sunday was described as critical.

He sought refuge in a nearby salon in the wake of the stabbing, but Khan's alleged attack was not over yet.

When police from Macquarie Fields arrived at the scene, he allegedly tried to stab an officer through a window before he was arrested.

A large knife was seized for forensic examination .

Khan was later charged by the joint counter terrorism team with committing a terrorist act and attempted murder.

Police say the attack was "planned" and "deliberate" despite the victim and Khan being unknown to one another.

"This was clearly a very volatile, a very violent situation that police and the members of the community were confronted with," Deputy Commissioner Catherine Burn told reporters on Sunday.

The accused allegedly shouted words at the scene, which led police to believe he was inspired by ISIS.

"We know that this person has strong religious beliefs inspired by ISIS. What made him act yesterday we don't know."

"It was deliberate and it was violent."

Federal Attorney-General George Brandis said police would allege that material related to the terrorist organisation Islamic State had been recovered in a search of the man's home.

"It is ISIL-related material but beyond that I'd prefer, given this matter is still an ongoing investigation, not to be more specific," Senator Brandis told reporters in Brisbane.

Senator Brandis thanked by-standers who intervened at grave risk to their own lives and safety.

"It may very well be but for the bravery of those citizens to intervene the victim's life would have been lost," Senator Brandis said.

"They are an inspiration to us all, they acted heroically and we should all be in their debt."

Ms Burn confirmed Khan was previously known to police but not in connection with any terrorist group.

"He has had a couple of interactions with local police over matters where we might say his behaviour was odd or unusual.

"He has been of concern, he is a person of concern...

"There may have been some behaviours in the past which might be concerning behaviours but not be linked to any of the matters that we are following or any of the people on our radar," she said.

"We will be alleging before court that this was an act that was inspired by ISIS, it was a deliberate act yesterday, it resulted in a person receiving extremely serious injuries," she said.

"This really highlights the challenge that this is the new face of terrorism, this is the new face of what we have to deal with."

Police reassured the community "there is no ongoing threat in relation to this incident".

Khan was refused bail when his case came up at Parramatta Bail Court on Sunday.