Defence Minister Richard Marles says there is no longer any hope of finding alive the four soldiers missing after an army helicopter crash in the Whitsundays.

As air safety inspectors arrived at Hamilton Island on Monday, Mr Marles said the extensive operation in the area had turned to recovery.

“There was a catastrophic impact of the helicopter when it hit the water. There will be a full investigation and we should not be speculative about the accident beyond the fact that it was catastrophic. The wreckage, which has been retrieved, tells us that,” he said.

“As such the nature of the activities which are being undertaken in the Whitsundays have transferred from being ones of search and rescue to an activity of recovery.

“The families of the four aircrew were notified of this this morning.”

Captain Daniel Lyon, Lieutenant Maxwell Nugent, Warrant Officer Class Two Joseph Laycock and Corporal Alexander Naggs all remain missing after their Taipan MRH-90 helicopter crashed near Hamilton Island on Friday morning.

The chopper had been conducting joint military training as a part of Exercise Talisman Sabre.

Defence Force chief General Angus Campbell said most of the wreckage of the Taipan was yet to be recovered. The main cabin is among the missing parts.

“The investigation, like all air accident investigations, will scrutinise every aspect of this event and we will be seeking to recover as much is possible of the airframe and for as long as required to assist in that investigation,” he said.

“There are data recording systems, so that will be of assistance, but the material and mechanical state of the airframe, as in other investigations, can be meticulously put back together and hence, understood.”

Mr Marles and General Campbell refused to give full details of the recovery mission.

Hundreds of Australian Defence Force personnel, including specialist navy divers and crews from HMAS Brisbane, HMAS Adelaide and USS Miguel Keith have joined Queensland Police in their search for the missing Taipan.

An exclusion zone has been imposed south of Hamilton Island, from the southern tip of Long Island east to Perseverance Island, south to Cole Island and west to the mainland at Round Head.

“We will do everything possible to bring those [four men] home to their families,” General Campbell said.

Captain Daniel Lyon, Warrant Officer Class Two Joseph Laycock, Corporal Alexander Naggs and Lieutenant Maxwell Nugent remain missing. Photo: AAP

Mr Marles said he had spoken to the families of the missing men on Monday, vowing that “the determined recovery effort” would continue.

“We are all obviously left wondering what happened. Foremost in our minds in this moment must be the families of these four men and their teammates. And with them in mind, idle speculation is obviously harmful,” he said.

“But there will be a full investigation and we will come to understand exactly what happened and learn the lessons from it. But what we do know is that defence exercises are serious. They carry risk, and as such, they are dangerous, but they are so important.”

It is the second time an Australian MRH-90 has been involved in an emergency this year after a Taipan ditched off the NSW south coast in March.

Forty-seven MRH-90 helicopters have been grounded until further notice.

Mr Marles said they had been due to be retired at the end of 2024, and their replacement Blackhawks would be fast-tracked.

“We will move through the process of putting the Blackhawks into service as quickly as we can, but as thoroughly as we need to, and we will not be flying MRH-90s until we understand what has happened,” he said.

The Talisman Sabre training operation involves defence forces from Australia, the US and a host of other allies.

The joint exercises, mostly being held in regional Queensland, resumed late on Saturday in the Northern Territory and Western Australia after an initial pause.

General Campell said exercises had also resumed in the Whitsundays, although modified around the search zone.

-with AAP