An overseas student who was king-hit at a McDonald's restaurant in Kings Cross says the unprovoked attack left him with a "face like a monster".

Rafael Daza, 34, was taken to hospital with severe facial injuries following the assault in the crowded fast-food restaurant on Darlinghurst Road in the early hours of May 9.

He was knocked unconscious, falling to the ground.

In CCTV footage released by police, a man appears to accuse the Peruvian national of spilling a drink belonging to a female friend.

He then king-hits Mr Daza, causing severe facial fractures, bleeding and bruising.

"This affected me, especially psychologically," said Mr Daza, who has lived in Australia for 18 months studying hospitality.

He said the attack left him with a "face like a monster".

"Now I can't work, can't study, sometimes I am very scared."

Detective Inspector Darren Schott says it appears Mr Daza was waiting in line when he was confronted by a solidly built Caucasian, aged about 25.

"It's sad to think this attack was over something as innocuous as an accidentally spilt drink," he said today.

The detective said Mr Daza had offered to buy a new drink, despite the fact that both security footage and witness statements suggest he had nothing to do with the spillage.

The man's female friend, aged in her early 20s with a slim build and long brown hair, is also believed to have tried to calm down the situation.

Mr Daza, whose insurance doesn't cover the surgery needed on his nose, says he will return to his studies once he has saved enough money for the procedure.

"I think I will continue to study. This could happen to anybody, not only me ... I was unlucky at that moment," he told reporters.

"I feel very proud because police are working hard to find this guy."

Inspector Schott called on anyone with information about the attack to contact police, saying they could remain anonymous.