DNA testing has indicated several bones found on the state's mid-north coast last month are those of missing French backpacker Erwan Ferrieux, NSW police have said.

Key points: Erwan Ferrieux and Hugo Palmer were last seen on a beach near Port Macquarie in February

Erwan Ferrieux and Hugo Palmer were last seen on a beach near Port Macquarie in February Bones were found on a beach last month close to where the pair were last seen

Bones were found on a beach last month close to where the pair were last seen A new search of local beaches has been launched

Mr Ferrieux, 21, was last seen near Shelly Beach — just south of Port Macquarie — in February, along with 20-year-old British tourist Hugo Palmer.

Their belongings, including towels, sunglasses and car keys, were found in a rental car nearby.

Police believe the pair may have drowned.

Last month, members of the public found three bones south of nearby Flynns Beach.

Those bones were matched against DNA found in the backpackers' vehicle.

"We believe from the DNA comparisons that [they belong] to Erwan Ferrieux," Superintendent Paul Fehon said on Monday.

Another bone, believed to be human, was found at Rocky Beach — about 300 metres north of Flynns beach — on Sunday.

The car left by the two backpackers off the beach at Port Macquarie. ( Supplied )

It has been sent to Newcastle, where a forensic analysis will determine whether it belongs to either of the missing backpackers, police said.

"We wouldn't be speculating at all and we'll be awaiting further tests to confirm that," Superintendent Fehon said.

"This bone is from another part of the anatomy."

Police said the new DNA analysis could take several weeks.

Following the discovery on Sunday, a new search of local beaches has been launched.

"SES personnel will be assisting with a search later today at low tide, but at this point in time police divers won't be attending," Superintendent Fehon said.

NSW Police have asked beachgoers to alert police if they believe they have found remains.

Police conducted a massive air, water and land search around the area when the pair were first reported missing.

The search was scaled back days later after it failed to find any sign of the backpackers.

At the time Mr Palmer's mother flew in from overseas to help with the search and attended a beachside vigil organised by the local community.