The search has resumed for a missing MRH-90 Taipan helicopter that went down in waters off Queensland's Whitsunday Islands with four crew members on board.
The aircraft was conducting joint military exercises as a part of Operation Talisman Sabre when it crashed near Hamilton Island about 10.30pm on Friday.
Talisman Sabre Exercise Director Brigadier Damian Hill told reporters on Saturday the missing crewmen came from the 6th Aviation Richmond Unit based at the Holsworthy Army barracks in Sydney.
He said their families had been informed of the accident.
Queensland Police Assistant Commissioner Douglas McDonald confirmed some debris had been recovered.
He urged any members of the public who found debris on the beaches around Hamilton or Dent Islands to contact police.
"At this time we have located a number of items of debris that would appear to be from the missing helicopter," he said.
"Can I encourage if any members of the community are on those beaches and come across anything that they might think is debris related to this particular incident, if they can contact police immediately and don't touch the items."
Brig 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.
He confirmed 47 other MRH-90 Taipan helicopters have been grounded until further notice.
The aircraft was involved in Exercise Talisman Sabre, a training operation that 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 Northern Territory and West Australia after an initial pause following the accident.
