At nearly 100 years of age, the last two survivors of the sinking of HMAS Perth off Indonesia have shared their extraordinary stories of survival at the opening of an exhibition to mark the 75th anniversary of the disaster.

David Manning, 94, described the moments that followed the order to abandon ship before midnight on February 28, 1942. He was 18 years old at the time.

"I was actually blown off by the four torpedoes that hit the ship," he said. "I have no memory of it other than sort of corkscrewing through the water."

Fellow veteran, 98-year-old Frank McGovern was also lucky to survive.

"As I jumped, I went down under the ship and the propeller," he said.

"I could see the phosphorous in the water. A huge blade going around, and then another one. And I was dragged in towards it.

"I thought, 'well, this is it'. I said my last prayer."

"I was turned over and over as though in a giant washing machine.

"And then shot out and almost came completely out of the water gasping for air of course," he said, smiling. "Nothing much left in the tank."

Battle came at Australia's lowest point of the war

Navy Fleet Commander Rear Admiral Stuart Mayer said the battle, in which more than 1,000 sailors were killed aboard the Perth and USS Houston in the Sunda Strait, came at the lowest point for Australia during WWII.

There had been the sinking of HMAS Sydney and HMAS Parramatta, the bombing at Pearl Harbour and the fall of Singapore. Then Darwin was bombed.

Rear Admiral Mayer said "the two ships were exhausted, outclassed and outnumbered".

"But despite the odds they turned towards the fight," he said.

"We remember them because their example of ordinary people doing extraordinary things is our heritage."

Mr Manning clung to a net for 10 hours before being rescued.

HMAS Perth arriving in Sydney for the first time, March 1940. ( Supplied: Royal Australian Navy - Naval Heritage Collection )

"I was clad only in a coating of oil fuel," he said, adding that he spent the next two weeks trekking through the mountains in Java, where he encountered a local woman.

"In about the second or third village I walked through, an elderly lady, in a very embarrassed manner, came out and offered me a piece of cloth about the size of two handkerchiefs which I was able to hold in front of myself until a bit later in the day when I managed to get hold of a sarong from a native trader."

Mr Manning was later captured and spent three-and-a-half years as a prisoner of war.

"Hardly a day goes past without some memory flying into your brain," he said.

"Some bad. I've never discussed the, shall we say the horrors — it's a strong word — even with my family as the kids were growing up.

"I always had a fund of funny stories that we had in real life. There were lots of those."

So how did he make it through an event that killed a third of the 688 men who were captured?

"You're not the first person to ask that and I can't give you an answer," Mr Manning said.

"I really don't know. Nobody's more surprised than me to find myself as the second last or last or whatever."

Mr McGovern survived two separate torpedo attacks that sunk the ships he was on, laboured on the Burma railway and endured a bombing raid that fractured his spine.

He said it is possible to survive the most abominable circumstances.

"If you've got your mates with you, yes," he said.

"And what I had, faith. Knowing that we wouldn't get beaten. That we would win in the finish. Although at times it didn't look like it."

Wreck site lives on as a memorial

Foreign Minister Julie Bishop said Australia's relationship with the United States was strengthened during the darkest days of WWII, and that Australia and Indonesia were committed to preserving the wreck site.

Ms Bishop said it was "a tomb for the brave servicemen — all 1,071 from our two cruisers who were killed during that battle".

One of the last views of HMAS Perth, en route to the Java Sea, February 1942. ( Supplied: Royal Australian Navy - Naval Heritage Collection )

"Only 40 per cent of HMAS Perth remains. Less than half of the wreck remains because it has been significantly damaged by illegal salvaging."

The Australian Government welcomed Indonesia's decision to declare the site a marine conservation area.

"We owe it to the servicemen who were killed," Ms Bishop said, before thanking Mr Manning and Mr McGovern, who she said were "remarkable men representing an extraordinary generation".

98-year-old Frank McGovern and 94-year-old David Manning with Foreign Minister Julie Bishop at the opening of the exhibition at the National Maritime Museum. ( Supplied: Australian National Maritime Museum )

The Indonesian Ambassador to Australia, Kristiaro Legowo, said the countries would work together to protect the remains of the ship.

"I'm pleased to hear the story of mateship continue," he said.

The Guardians of the Sunda Strait exhibition is at the Australian National Maritime Museum until November 17, and will then travel to Perth.