A recovery search continues for the bodies of Captain Danniel Lyon, Lieutenant Maxwell Nugent, Warrant Officer Class Two Joseph Laycock and Corporal Alexander Naggs.
The MRH-90 Taipan helicopter crashed near Hamilton Island on Friday night.
The chopper had been conducting joint military training as a part of Exercise Talisman Sabre.
Defence Minister Richard Marles said the search and rescue operation was now a "recovery" mission and family members had been informed.
He said evidence showed there had been a "catastrophic incident" and any hope of finding them alive was now lost.
"We are all left wondering, naturally, what happened (and) foremost in our minds in this moment must be the families of these four men and their teammates," Mr Marles said.
"There will be a full investigation and we will come to understand exactly what happened and learn the lessons from it."
Mr Marles said the loss of the four men was "significant and meaningful".
"They died on Friday night making a difference," he said.
Chief of the Defence Force, Angus Campbell, offered thoughts and prayers to the families and friends.
"I'd ask all Australians to pause for a moment and think about that service offered, and the loss suffered and to support and care for these families," he said.
General Campbell said due to the depth of the currents, sonar equipment had been used to identify pieces of the wreckage.
"This effort will continue. We will be bringing our mates home to their families and to their regiments," he said.
A full investigation into the crash will take place.
Forty-seven MRH-90 helicopters have been grounded until further notice.
Mr Marles said the helicopters were certified to fly.
Specialist navy divers joined Queensland police and crews from HMAS Brisbane, HMAS Adelaide and USS Miguel Keith in their search for the missing Taipan.
An exclusion zone was put in place 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.
It is the second time an Australian MRH-90 has been involved in an emergency this year, after a Taipan crashed into the sea off the NSW south coast in March.
Talisman Sabre has more than 30,000 defence force personnel participating from more than a dozen partner nations including the US.
The joint exercises, mainly being held in regional Queensland, resumed late on Saturday in the Northern Territory and Western Australia after an initial pause.
17°C