POLICE have scaled back the search for a British tourist and his friend missing from a beach in Australia.

New South Wales Police said it was reducing the air and sea search for Hugo Palmer and Erwan Ferrieux on Wednesday, more than two days after their belongings were found on Shelly Beach, near Port Macquarie on the New South Wales coast.

Walkers found items belonging to the 20-year-olds at about 6.30am on Monday, and police later discovered their rental car in the beach's car park with a number of personal items, including travel documents, inside.

Despite efforts from emergency services, including police divers, to locate them, there has been no sign of the two men.

"Based on advice from experts, police have scaled back the air and sea search, but sweeps of the coastline and foreshore will continue over the coming days," a spokesman for the force said.

It is believed Mr Palmer, from East Grinstead and Mr Ferrieux, a French national, had arrived in Australia in November, and had been in the Port Macquarie area since Sunday.

Earlier on Wednesday, Inspector Peter Neville said he still had hope of finding the two men alive.

"This whole operation is about locating and rescuing these young men. From some of the discussions I've had this morning we honestly believe these people could well be alive," he told the Port Macquarie News.

"At the moment this is strictly a rescue mission."

Mr Neville said two of the men's friends, who were in Sydney at the time of their disappearance but were due to meet up with them, had travelled to Port Macquarie to support the search.