Memorial services marking the 50th anniversary of Australia's worst peacetime maritime disaster are today taking place at Jervis Bay on the NSW south coast.

Eighty-two men on board HMAS Voyager were killed after it collided with aircraft carrier HMAS Melbourne during a training exercise on February 10, 1964.

The Voyager was cut in half, but 232 people survived.

Many of the survivors will join with families of the victims and dignitaries for several commemorations, starting at 8:30am today with a memorial church service at HMAS Creswell's chapel.

One of the main events on Monday will be a memorial service at the wreck site of HMAS Voyager, about 20 nautical miles off Cape Perpendicular.

There will also be a sunset ceremony with an 82-bell toll to honour each life lost.

The HMAS Melbourne at sea off NSW following a collision with the destroyer HMAS Voyager on the night of Feb. 10, 1964. ( Courtesy of the Australian War Memorial )

The tragedy has had ramifications for years, with many sailors experiencing post traumatic stress disorder (PTSD).

There was no counselling, just a week's survivor's leave.

The subsequent cover-up by the Government and the Navy led to an unprecedented two royal commissions in pursuit of the truth.

Both inquiries were critical of the Voyager's captain and the second inquiry examined new evidence about his drinking and health.

Captain Duncan Stevens was eventually deemed unfit to command due to medical reasons.

But some survivors do not want to take part in the commemoration ceremonies.

"A lot of them, I think, have just found if they don't acknowledge it and shut it up, bottle it up, it never happened," survivor 'Bluey' Ducker said.

"They don't want to remember, don't want to even associate with their old shipmates."

Re-fitted ships 'not up to speed'

The former Chief of the Defence Force, Admiral Chris Barrie, has reflected on his own experience of the Voyager disaster 50 years ago.

Admiral Barrie was a young cadet at Jervis Bay when the HMAS Voyager collided with the aircraft carrier HMAS Melbourne.

He lamented the loss of life and the lack of information about what really happened.

"We're never really going to know what happened on the night of the collision, except when I look at the paperwork what I see is two ships in post refit trials," he said.

"Neither had been at sea for very long, and having been through post refit trials myself I know that the ships weren't up to speed in operational capacity."