The young man, believed to be in his twenties, was found bloodied and unconscious following an alleged attack by a group of up to eight Asian men outside Capital Square on Campbell Street, Haymarket at 4am.
It is understood the victim stopped breathing twice and had to be resuscitated at the scene by paramedics.
According to one eyewitness, who alerted police to the incident, the violent attack was sparked when the man approached the group asking for cigarettes or money.
"One of the guys threw a cigarette in his face. I went to the traffic lights and then I looked back and he was on the ground, with four of the blokes around him, " Mr Ammar, a taxi driver, said.
"I saw the last kick (to the man assaulted)".
"It looked like he started it. He was very close to them, asking for stuff. One of the Asian guys was trying to mediate and he just pushed him back. The idiot just kept persisting."
"Something must have gone wrong in the 30 seconds that I went up to the traffic lights. It happened so quickly."
Mr Ammar said he drove around the corner and alerted police.
"I told them there was a guy left unconscious on the ground."
The taxi driver confirmed the young man was by himself when he approached the group.
Police Inspector Sean Heaney said three young men, who were also in their twenties and of the same Thai background as the victim, were arrested nearby and taken into custody.
"They certainly didn't stick around. They were a few blocks away when we got them," Inspector Heaney said.
He confirmed the paramedics administered CPR before taking the victim to St Vincent's hospital in a critical condition with head injuries.
A spokesman for St Vincent's Hospital this morning said the man remained in intensive care, but was now in a stable condition.
He said the man was being treated for head injuries.
- Daily Telegraph Australia