A father desperately tried to rescue his two sons from rough surf off the Victorian coast before one of them went missing.

Emergency services resumed a search on Saturday for the missing young man after being called to the Gunnamatta surf beach on the Mornington Peninsula on Friday night.

The father noticed his sons, aged 20 and 16, were struggling and went in to help them.

Rescuers managed to pull the father and the teenager from the water, but the older son could not be located.

“It was a heavy swell and strong winds at the time,” Victoria Police Acting Inspector Ian Pregnell said.

Police, surf life savers and State Emergency Services personnel, including helicopters and fixed wing aircraft, were initially deployed in the search on Friday.

Helicopters were seen still circling the beach on Saturday.

The rescued father and the teenager were hospitalised with non-life threatening injuries.

-AAP