As Australia marks Anzac Day, historians in Singapore fear not enough is being done to preserve important World War II sites.

The infamous Changi jail and nearby barracks held more than 35,000 Allied soldiers during WWII, including 15,000 Australians.

With land at a premium in the island nation, Singaporean authorities have built over the top of many historic sites and destroyed wartime buildings.

The key remnants of the Changi jail are a section of wall and a gate, but both are on land used for Singapore's prison constructed in 2005 and are not publicly accessible.

The current military barracks, also not accessible to visitors without special permission, is home to a chapel with five biblical-themed murals painted by prisoner of war Stanley Warren, as well as the WWII-vintage officers' mess.

The Changi museum, which lies close by the barracks and jail, has a number of artefacts, including an original cell door, barbed wire and a piece of prison wall, as well as replicas of the murals and an outdoor chapel featuring prisoner of war (POW)-made items from the period.

Historian and Changi museum operator Jeyathurai Ayadurai said he recognised that land was at a premium, but Singaporean and Australian authorities needed to look at innovative ways to preserve wartime history.

"We went through a process from the 1980s where a lot of historical sites were lost," Mr Jeyathurai told AAP in an interview in Singapore.

"We've lost almost all of Changi."

He said one option he was suggesting to both governments was to set up - initially online - a nominal roll of all men and women involved in the fight for Singapore, as well as the thousands of civilians who were interned.

The number of names is estimated to be around 142,000.

"We plan to launch a virtual Changi wall," Mr Jeyathurai said.

"It would be with an intent that the information at some point go onto the physical wall (housed in the new jail) and be preserved."

He said a suitable launch date for the project would be September 12, 2015 - the 70th anniversary of the signing of the surrender document by the Japanese in Singapore.

"We can think of no more appropriate way to commemorate that," Mr Jeyathurai said.

Another idea being floated with Singaporean and Australian authorities was to build a museum at the Kranji war cemetery in the north of the island.

While the cemetery is a poignant and well-maintained reminder of more than 28,000 soldiers and nurses who died, there is no readily available information at the site for the public.

Mr Jeyathurai said he'd like to see a joint committee of Singaporean and Australian authorities and interested parties established to look at this and other ways to mark the 70th anniversary of the end of WWII.

"It's critical that every generation is aware of the sacrifice that was made, and there's a lot of goodwill on both sides - Australia and Singapore - to achieve that," he said.

Singapore-based Australian historian Kevin Blackburn said he agreed there had been little progress on turning the original Changi wall into a memorial and even those who did get permission to see it were made to delete any photos from their cameras by the prison officers.

There was also the prospect of the prison expanding, which made it all the more important to preserve Changi's heritage.