A man has been dramatically arrested in Sydney's CBD after going on a stabbing spree in Sydney's CBD.
Police are yet to confirm whether the death is linked to the attack in the city. En route to the location, police received further reports that a woman had been stabbed.
The man was detained by members of the public before being arrested by police.
The Clarence Street entrance to Wynyard Station is closed.
Police on the scene at King St and Clarence St have advised people to avoid the area.
Detective Superintendent Gavin Wood told reporters that they intervened in the face of "incredible danger".
"These people are heroes, and I want to acknowledge that". "They were fearless and I can only use that word seriously", he said.
"They were courageous, and and i can only use that word seriously, they were significantly fearless people".
"We don't know the causation or rationale for his actions today, again its part of the investigations as we go forward".
A witness told 2GB he hit a young man who ran in front of his auto on York Street.
Witnesses report that a man was seen running through the area armed with either a large knife or a machete.
"He held the knife in the air and started screaming", she said.
"My immediate impression was that it was a scene from a crime show being shot, but then that quickly turned out not to be the case and the man ran down the road towards the cafe where patrons there must have tripped him up and they then put a milk crate over his head".
"There is a police operation that is ongoing in the CBD", a police spokesperson said. There was fireys chasing him with axes and he went around the corner.
"What I can say conclusively, that male offender was on his own. and there's no other person complicit at this stage".
He said the crowd was "shaken up, that's for sure".
Eye witnesses said members of the public swarmed the man and pinned him to the ground using a chair and a milk crate, after he was spotted walking around King and Clarence Street having tried to stab multiple people.
A witness can be heard saying "he just stabbed a chick in broad daylight".
An Uber driver, Leon, reportedly told 2GB that a shirtless man covered in blood and carrying a knife had leapt across the bonnet of his vehicle.
Paul O'Shaughnessy, 37, said his brother Luke, 30, saw a man with a balaclava wielding a knife. He said the man, who appeared to be 23 or 24 years old, had blood on his shirt and appeared to be agitated.
Prime Minister Scott Morrison tweeted his support.
"Our thoughts are with all those who have been impacted by this violent attack", he tweeted.
The motivation for the attack was not yet known, they added.
#BREAKING: Police address the media after a woman was stabbed in the Sydney CBD.
He praised those who had intervened in the "extremely unsafe and hostile" situation, saying their actions had helped capture the man.