Children, related to a man stabbed multiple times at a Blue Mountains shopping centre, watched as the attack unfolded, police say.

Members of the public rendered first-aid to the 41-year-old, who suffered life-threatening injuries during the attack at the Hazelbrook Shopping Centre shortly before 6pm, acting Superintendent Paul Glinn of Blue Mountains Local Area Command told the Blue Mountains Gazette.

He said the argument started in a shop before spilling out into the car park.

"He sustained a number of wounds to the chest and the neck, which were considered life threatening last night," he said.

"It would appear that it wasn't a random incident. However, the exact nature of the relationship between the people is something which is still being investigated."

There were reports the attack may have followed a schoolyard fight earlier in the day, but acting Superintendent Glinn said he was unaware of any such connection.

"Certainly it's the case there [were] some children and other people present in the area at the time that the incident has occurred.

"There were a number of children there that I believe are related to the 41-year-old victim."

Ambulance crews stabilised the man before he was flown to Westmead Hospital, where he underwent emergency surgery overnight.

A 50-year-old man was arrested about 7pm yesterday and was charged at Katoomba police station this morning with reckless wounding causing grievous bodily harm.

He was refused bail and will appear before Katoomba Local Court today.

Police expected to interview the victim either tonight or tomorrow morning and were also interviewing between 20 and 25 witnesses, acting Superintendent Glinn said.

"Consistent with any shopping centre, Hazelbrook Shopping Centre at 6 o'clock on a Monday night, there'd be a lot of people there," he said.

"There's a train station nearby, people would be walking home, so there certainly would be people about the area going about their normal day-to-day business."

It was unclear how many times the victim was stabbed and police were still unclear what weapon was used in the attack, he said.

CCTV from the area would also be used in the investigation, he said.

"Any incident whereby it's alleged that somebody may have been in possession of a knife or some other sort of weapon whereby some injuries have been occasioned to somebody else is of significant concern," he said.

"The good thing from our perspective is it's not something that occurs on a regular basis and it would appear that this is a one-off incident.

"The exact nature as to what was used is unknown and ... from our perspective, if anyone was there that witnessed the incident and has not made themselves known to police, we'd ask they make contact with police so that we can follow up any information they may have."

Blue Mountains Gazette