The Australian Defence Force has been asked to help in the recovery mission of three US Marines killed in an aircraft "mishap" off the Queensland coast.

The Marines were among 26 personnel aboard an MV-22 Osprey that crashed while attempting to land on the USS Green Bay during a training mission about 4pm yesterday.

The Osprey went into the water off Shoalwater Bay, near Rockhampton.

A search and rescue mission using small boats and aircraft successfully retrieved 23 Marines, but failed to locate the last three.

This file photo shows a MV-22, similar to what crashed off the coast of Queensland. (File)

One Marine was flown by helicopter to the Rockhampton Base Hospital with a fractured leg, before the chopper returned to aid in the search.

Today, a spokesperson from the III Marine Expeditionary Force confirmed that after an extensive overnight search there was no longer hope of finding the three missing Marines alive.

"Operations have now shifted to recovery efforts. The next-of-kin for the three missing Marines have been notified," the spokesperson said.

Efforts now turn to recovering their bodies, and for that mission the US military has requested the assistance of the ADF.

Families of the three missing US Marines have been notified, the III MEF Marines said in a Facebook post. (III MEF Marines)

The ADF are assisting with a recovery mission. (III MEF Marines)

Australia's Defence Minister Marise Payne has extended the nation's condolences to the families of those killed.

"I have briefed Prime Minister Turnbull and spoken with Secretary Mattis this evening to offer Australia's support in anyway that can be of assistance," she said in a statement yesterday.

The MV-22 Osprey is a unique aircraft that is part-helicopter, part-plane.

It has capabilities unlike any other but it has had a chequered history since it entered service.

Since launching in 2007, the aircraft has had five serious crashes, causing nine other deaths.

The US Marine contingent have been in Australia for several weeks to take part in Talisman Sabre, the largest war games exercise to involve our two countries.

The training exercise had been considered a success prior to this tragedy.

US Marine Corps Commandant Robert B Neller asked for the public think of the families of those involved.

"Please keep the families of those involved in the Osprey mishap near Australia in your thoughts and prayers," he tweeted.