Sydney returned to the "bad old days" with a weekend of alcohol-fuelled violence in the streets, St Vincent's Hospital's head of emergency says.
"This weekend just past has been so scary," Professor Gordian Fulde said.
"People were punched, knocked to the ground, also kicked.
"We had people with their teeth kicked out," he told the Seven Network on Monday.
It comes after a 32-year-old man was charged over a one-punch attack outside a fastfood restaurant at Bondi Beach that left a young man badly injured.
The man from Hillsdale, in southeast Sydney, was charged with recklessly causing grievous bodily harm after allegedly punching Jake Stephenson, 21, in the back of the head and then kicking him in the chest as he lay on the ground.
Mr Stephenson was rushed to St Vincent's Hospital in the early hours of Sunday and placed in an induced coma.
His condition improved and he was released from hospital on Sunday but will need ongoing treatment, police said.
Prof Fulde says there were quite a few similar attacks on the weekend.
"I'm really frightened we're going back to our bad old habits," he said.
Prof Fulde believes the arrival of the warm weather has brought people out into the streets and says alcohol is the trigger behind the violent attacks.
"(It's) purely people who have drunk too much. People get enraged about nothing, they're hitting people.
"It's unacceptable."
He said there had been a massive drop in the number of severe head injuries since the February introduction of lock-out laws designed to combat alcohol-related violence - until this weekend.
On February 24 there has been 1.30am lockouts and 3am last drinks laws across the Sydney CBD Entertainment Precinct.
But Professor Fulde said last weekend people were so drunk they fell backwards off balconies and stairwells.
Mr Stephenson, believed to be from the NSW south coast, hit his head on the concrete as he fell to the ground.
His alleged attacker turned himself in at Waverley Police Station on Sunday and was arrested.
He was granted strict conditional bail to appear in Waverley Local Court on November 19.
