A search has resumed for a pilot and four passengers who are feared dead after a helicopter crashed into waters off the NSW coast.

Police are spearheading the recovery operation after the Bell UH1 helicopter dropped off the radar near Anna Bay, north of Newcastle, early on Friday night.

The aircraft belonged to Brisbane Helicopters owner and pilot David Kerr, who is believed to have been flying it at the time.

Queenslanders Jamie Ogden and Grant Kuhnemann and NSW couple Jocelyn Villanueva and Gregory Miller are also believed to have been on board.

NSW couple Jocelyn Villanueva and Gregory Miller. Photo: Facebook

The Australian Defence Force on Sunday confirmed Mr Miller as a warrant officer but said he was not on duty at the time of the crash.

Mr Ogden’s brother, Darren, has flown to Nelson Bay from Queensland after hearing about the crash.

“He said he was going down with his mate Dave and a few others and they were going to leave the chopper down there and have a night in Sydney and fly home back to Brisbane on Saturday,” Darren Ogden told the ABC.

“They were looking forward to that, flying down the coast at fairly low level, looking forward to it being a great trip.”

The Australian Transport Safety Bureau (ATSB) is investigating, with officers from Canberra travelling to the area to examine the recovered wreckage, interview witnesses and inspect aircraft and pilot records.

The bureau on Sunday called for any witnesses to make contact as they investigate the circumstances of the crash.

“Witness reports can help provide invaluable information to ATSB investigators as they begin the task of determining the circumstances of this tragic accident,” the bureau said on Facebook.

“The ATSB expresses its deepest sympathies to the families and friends of those on board the helicopter.”

The Australian Maritime Safety Authority (AMSA) said the helicopter had been on a private flight between Coffs Harbour and Bankstown in Sydney’s southwest. It launched the search for the aircraft on Friday night and spotted an oil slick and several pieces of debris.

Most of the wreckage was located on Saturday, with the helicopter’s tail rotor found by water police about 8.45am.

A Westpac rescue helicopter spotted the main airframe less than an hour later, roughly eight kilometres south of Fingal Bay. They watched as it sunk before boats could retrieve it. The location was consistent with where the aircraft is believed to have crashed.

“There have been no sightings of the occupants of the helicopter,” the AMSA said in a statement.

The aircraft went missing amid poor conditions with low visibility, high winds and dust in the air.

Air traffic control indicated the aircraft was rapidly losing altitude when contact was lost, and there were no emergency beacons signals or mayday calls detected.

Civil Aviation Safety Authority records show the 1960s US military helicopter – famously known as a “Huey” – was registered for use by Brisbane Helicopters in October last year.

-with AAP