A NSW Police Marine Command crew equipped with sonar and underwater cameras spent Thursday patrolling an area about five kilometres from the shore.

It was the first time since the helicopter crashed that conditions were favourable enough for a detailed search to be undertaken.

Specialist police divers were also on board in the event that the 1960s-era Bell UH-1H Iroquois helicopter was located.

The search will resume on Friday, conditions permitting.

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It is still hoped the bodies of those believed to be on board - Queensland men Jamie Ogden and Grant Kuhnemann, Sydney couple Jocelyn Villanueva and Gregory Miller, and the chopper's pilot and owner David Kerr - also from Queensland - can be recovered.

The helicopter disappeared from the Williamtown air traffic control radar at 6.49pm. No emergency beacon signals or mayday calls were detected.

The Newcastle Herald reported earlier this week that part of the helicopter wreckage was spotted at about 8km south of Fingal Bay on Sunday, but it sank before being collected.

The Air Transport Safety Bureau is investigating how the helicopter, which departed from Brisbane and stopped to refuel at Coffs Harbour before the crash, ran into trouble.

The bureau expects to complete a report on its investigation in the second quarter of next year.

Police are continuing their call for witnesses who may have been in the Anna Bay or Fishermans Bay area between 5pm and 7pm on Friday who may have pictures or footage of the helicopter.

Police are urging witnesses to contact Crime Stoppers on 1800 333 000.

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