Dramatic footage has emerged of a stranded diver clinging to rocks as huge seas batter all around him being rescued via winch.

The man was one of two hypothermic snorkellers who were rescued just south of Pauanui Beach on the Coromandel Peninsula just before nightfall on Saturday.

Two men were rescued from this rocky cliff south of Pauanui. Photo / Westpac Rescue Helicopter

The men had gone snorkelling off the rocks at the Pauanui conservation area, but hadn't returned by 5.45pm and the alarm was raised.

At about 6pm on Saturday Whitianga-based crew of the Auckland Westpac Rescue Helicopter were tasked by police to assist in the search and rescue operation

The men were sheltering from an incoming tide and large swells. Photo / Westpac Rescue Helicopter

They were found just before last light of the day, trapped clinging to rocks.

The men had been there since about 2pm with big swells battering the rocks all around them.

Two men were rescued from this rocky cliff south of Pauanui. Photo / Westpac Rescue Helicopter

With a rising incoming tide, the snorkellers were separated from each other by about six to seven metres.

Video shootage taken by Pauanui Coastguard Rescue show Westpac 1 Intensive Care Paramedic Ross Aitken being winched down to lift the two men off the rocks.

There was barely enough room for Aitken to position his feet on one of the ledges to save one of the men.

Crew chief Mark Cannell, who operated the winch, said it was some of the most trying conditions he had been in.

"It was touch and go. I'm pretty sure they wouldn't have survived if we hadn't got there in time. Certainly one of them wouldn't have made it."

The two men were slightly hypothermic but didn't need to be transported to hospital.