Homicide detectives have joined the investigation into an alleged coward punch attack that has left a man fighting for life in a Gold Coast hospital.
Police said Michael Hayes, 39, was hit Saturday night by a man wearing a dark tracksuit outside Destino Wine and Cocktail Bar on Hope Island.
Mr Hayes remains in a critical condition at Gold Coast University Hospital with family at his bedside.
"He is on life support and we hope that he pulls through," Detective Inspector Chris Ahearn said.
Police believe interstate witnesses may hold the key to finding the person responsible.
The family precinct was full of diners who had been to the Sanctuary Cove International Boat show, which attracted visitors from across Australia.
Police said Mr Hayes left the bar to talk to a man who then delivered a single punch to the side of his head.
An interstate appeal
Police have appealed for anyone who saw the men talking to each other along Masthead Way between 9pm and 9:30pm to contact them urgently.
"We know there was a number of interstate visitors who may have [since] returned to their homes," Detective Inspector Ahearn said.
"I'd like to make an appeal to anyone who saw anything suspicious, or indeed this incident, or who took images on their phone, to please contact police," he said.
Police have issued a description of the unidentified person seen talking to Mr Hayes.
He is described as Caucasian, between 20 and 30 years of age and with short dark brown hair.