Mr Christie’s family say he died on Saturday morning at Sydney’s St Vincent’s hospital.

“While no words can describe how crushed we are, Daniel fought courageously over the past 11 days which allowed everyone to say their farewells,” the family said in a statement.

“It has also given us all strength and tightened even further the bond our family share.”

The 18-year-old was taken to St Vincent’s Hospital in a critical condition after being punched in Kings Cross on New Year’s Eve.

His alleged attacker, Shaun McNeil, has been charged with causing grievous bodily harm, assault occasioning actual bodily harm and three counts of common assault.

Police allege McNeil, 25, struck three young men before targeting Mr Christie and his brother, Peter, when the other young men tried to hide behind them.

McNeil, a labourer, allegedly boasted he was a mixed martial arts fighter before punching Mr Christie in the face as he shielded the other young men.

Through his lawyer, McNeil has previously told a court that the first group of young men was trying to sell him drugs and he acted to protect his girlfriend who was with him at the time.

He was unable to explain his actions towards the Christies, police facts previously tendered in court said.

A court has heard that doctors believed Mr Christie would probably have suffered a serious brain injury if he survived the attack.

Police say they expect further charges to be laid against McNeil, who is next expected to appear in court in March.

Describing their son as a beacon of morality, the Christie family said they want to see “coward punches” become a thing of the past.

“People have the right to go out without experiencing mindless violence,” they said in their statement.

“Therefore, if you are going for a night out, please honour Daniel’s memory by thinking before you drink.

“Make sure your mates don’t get carried away and do anything they’ll later regret.”

Mr Christie’s organs will be donated.

“Although we are absolutely devastated at the tragic loss of our Daniel, we believe by sharing such a special gift with those in need, he is well and truly living on,” the family said.

Mr Christie’s death comes 18 months after 18-year-old Thomas Kelly died after being hit with a single punch in Kings Cross in July 2012.

It is alleged that Mr Christie was hit just metres from where the attack on Mr Kelly took place.

Since Mr Christie was taken to hospital, there has been increased pressure on the NSW government to tackle alcohol-related violence on the late-night strip and introduce tougher sentencing for perpetrators.

NSW Attorney General Greg Smith expressed his sympathies to the families and said he had contacted the director of public prosecutions over the matter.

“I have spoken to the Acting Director of Public Prosecutions and asked him to closely examine this case with a view to determining if murder charges are appropriate in light of the evidence, and in light of the alleged offender’s reported martial arts experience,” said Mr Smith in a statement.

“These incidents have focused community attention on alcohol-related violence, and the government will be working with police to make our streets safer. Last month I met with the Kelly family and I am giving careful consideration to their proposals.”

In November, Mr Kelly’s parents Ralph and Kathy started a petition calling for drunkenness to be a mandatory aggravating factor that must be taken into account in sentencing.

The petition, started in November, was at about 25,000 signatures before New Year’s Eve.

But following the alleged assault on Mr Christie, that surged to more than 124,000.