Family and friends watched as thirteen United States citizens were today presented the New Zealand Special Service Medal (Erebus) for their work in "Operation Overdue", the body recovery, crash investigation and victim identification resulting from New Zealand's worst air disaster.

New Zealand Ambassador Roy Ferguson and Vice Chief of Defence Force Rear Admiral Jack Steer presented the medals to the recipients who included US Navy personnel and transport accident investigators.

Commodore David Anson, head of New Zealand Defence Staff in Washington, made a moving closing address and noted that there were still US personnel yet to be located so they could be presented with the medal.

"Today we have formally acknowledged the personal courage and commitment to a ghastly task in the wake of a tragic accident. The job of locating all the recipients of this award is not yet complete, and we still have another twenty or so to find and formally recognise."

Retired New Zealand Police Sergeant Mark Penn, the last searcher to leave Mount Erebus, spoke during the ceremony about the tragedy, the difficulty faced by all who were involved in Operation Overdue as they worked to the point of exhaustion, and the vital support from the Americans.

"From the very moment the US Navy launched its search, the American assistance to New Zealand in the recovery operation was unstinting, generous and extensive. For that we will always be grateful," said Sergeant Penn.

A video message from Prime Minister John Key was played during the medal ceremony, honouring the US citizens involved in Operation Overdue.