POLICE have arrested an 18-year-old man over the death of Thomas Kelly in Sydney's Kings Cross.

Homicide squad detectives arrested Kieran Loveridge, from Glendenning, near Mt Druitt in Sydney's west, at a Belmore sports field about 7.30pm.

The 18-year-old was interviewed at Campsie police station by strike force Mohawk detectives.

Just before midnight he was charged with one count of murder.

Mr Loveridge was also charged with three counts of assault relating to separate alleged attacks the same night.

Police allege Mr Loveridge, who turned 18 on March 9, king-hit Mr Kelly about 10pm on July 7 as he walked with his girlfriend on Victoria St, in Kings Cross.

A police source said Mr Loveridge was also in the Cross for a big night out. Mr Kelly, of Bowral suffered critical head injuries in the attack.

Two days later, in St Vincent's Hospital, his parents Ralph and Kathy made the heart-breaking decision to turn off his life support.

Police will allege that Mr Kelly was Mr Loveridge's first victim, followed by an attack a few minutes later on another man.

Two more people were then allegedly assaulted on Roslyn St.

Mr Loveridge had been at Belmore Oval watching a friend play football, although reports emerged last night that he had been watching a training session of the Canterbury Bulldogs.

He was handcuffed and taken from the ground.

Sources said that while Mr Loveridge spoke with police as he was being driven to the station, he declined to be interviewed.

Mr Kelly finished high school at The King's School last year and had an accounting cadetship while also studying commerce at Macquarie University at night.

Mr Kelly's shocking death has also led to an urgent review of safety along the notorious Golden Mile.

Gambling Minister George Souris ordered a four-day compliance blitz of 58 late-trading pubs and clubs.

The operation, which started on Tuesday, aims to assess the effectiveness of security, surveillance and incident reporting.

Mr Loveridge will face Burwood Local Court today.