By Kathryn Magann and Samantha Lock in Sydney

PRIME Minister Anthony Albanese has thanked Australia’s allies for helping in a search for the four crew of an army helicopter who are feared dead after the aircraft went down during joint exercises.

The desperate hunt for survivors from the Taipan helicopter crash resumed on Sunday, with navy divers joining the rescue and recovery operation.

The MRH-90 helicopter was conducting joint military training as a part of Exercise Talisman Sabre when it crashed in waters near Hamilton Island in Queensland about 10.30pm on Friday.

The prime minister said the incident was a stark reminder that there were “no safe or easy days for those who serve in our country’s name”, thanking all those involved in the search including foreign personnel.

“On behalf of our nation, our thoughts and prayers are with the families, friends and colleagues of those who are missing,” he told reporters on Sunday.

The missing crewmen are from the 6th Aviation Regiment based at Holsworthy Barracks in Sydney.

NSW Premier Chris Minns confirmed one of those feared dead following the crash was the son of a senior NSW police officer.

“(They’re) a family that’s given so much to the people of this state of this country,” he told Sky News.

“I can only imagine what they’re going through today. It’s just devastating.”

Some debris from the stricken helicopter was recovered on Saturday and Queensland police urged members of the public who found crash material in the Whitsunday region to contact investigators.

Talisman Sabre director Damian Hill said specialist navy divers would be deployed on Sunday when additional ships arrived with sonar equipment.

“The water is quite deep in and around the potential impact area,” he said.

“HMAS Huon has some of our more experienced divers should we need to look under the water for wreckage as the search and rescue continues.”

Brigadier Hill confirmed 47 MRH-90 helicopters had been grounded until further notice, although details of what might have led to Friday’s crash have not been revealed.

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

The helicopter has earned a reputation as unreliable in recent years, with malfunctions and technical issues forcing several earlier groundings of the fleet.

Nationals leader David Littleproud called for an “open and transparent” inquiry into the incident.

“(We should be) making sure that we give our defence force the very best tools that they need to be able to defend us,” he told Nine’s “Today” program.

Labor frontbencher Michelle Rowland said the focus at this stage should be on the missing personnel and their families, but there would be a full investigation into what led up to the crash.

The Talisman Sabre training operation involves defence forces from Australia, the United States and other allies.

The joint exercises, which are mostly being held in regional Queensland, resumed late on Saturday in the NT and WAafter an initial pause following the accident.