Services were held around the nation on Wednesday to mark the 67th anniversary of the loss of both ships and honouring the 645 crew on the HMAS Sydney and the 78 crew on the German raider Kormoran who lost their lives.

For more than 66 years, mystery protected the final resting place of more than 600 crewmen who perished when HMAS Sydney went down during a battle in World War II.

On the 67th anniversary of its sinking, and six months after the wreckage was finally found, the federal government has offered it permanent protection.

The loss of the Sydney with all 645 aboard, during a November 19, 1941 battle with the German raider HSK Kormoran, has always been remembered.

But relatives were able to pay their respects in a much more meaningful way on Wednesday, casting wreaths and other symbolic tokens into the sea above where the ship lies, 2,500 metres down.

“The sun is shining, the sea is calm, the wind is light and variable,” Commander Mandziy said from HMAS Manoora, which took 285 family members to the shipwreck site 207km north-west of Geraldton for a memorial.

Mandziy said it was an “electric occasion” full of emotion for those lost, and relief that the fate of the ship is finally known.

At a separate service in Geraldton, other relatives were finally afforded a sense of closure with the reburial of an unknown sailor, believed to be the only body ever recovered from HMAS Sydney.

It was a powerful moment for all those present when the casket of the man, draped in the Australian white ensign, was lowered into the ground at Geraldton’s Queens Park, having been honoured with The Last Post and a minute’s silence.

Prime Minister Kevin Rudd said Australia had marvelled at the discovery of HMAS Sydney and the Kormoran in deep water 200km off the West Australian coast earlier this year.

“Now the final resting places of the crews have been permanently protected,” Rudd said in a statement on Wednesday.

“For more than 66 years the fate of HMAS Sydney II and HSK Kormoran had been the subject of much public speculation and heartache and the finding gave the opportunity for closure for many families and friends of the crew.”

Temporary measures to prohibit unauthorised intrusion into the sites were introduced soon after the vessels were discovered, but both ships will now be protected permanently by law.

“We have now made these measures permanent under the Historic Shipwrecks Act 1976 prohibiting the damage, disturbance or removal of the vessels and their relics and requiring a commonwealth permit to enter the sites,” Mr Rudd said.

The government has also taken steps to have both sites added to the National Heritage List.

>> Pay your respects in London on Wednesday, November 19 at the HMAS Sydney Memorial Service