Former Victorian state premier Jeff Kennett will demand an apology from the Japanese Emperor and Tokyo after touring World War II prisoner of war camps in Borneo.

Kennett, who served his national service in Malaysia, returned to Australia last week after tracing the steps of Australian soldiers killed during the notorious Sandakan death marches during World War II.

"The treatment of these defenceless men was really unacceptable. The Japanese have never taken responsibility for what happened," Kennett told The Herald Sun newspaper.

British and Australian prisoners of war were sent to Sandakan to build an airport during World War II.

Kennett said the prisoners were starved, tortured and brutalised by Japanese army soldiers who then tried to cover up their heinous crimes by killing the prisoners at the end of the war.

"There was not a shred of decency shown towards these soldiers. The Japanese have never apologised, and it really was one of the worst war-time atrocities," he said.

Kennett said he had worked closely with and respected local members of the Japanese community, but would write to the country's government and Emperor to demand an apology.

"There are still many families that still do not know what happened to their fathers and brothers. It's important to them that the Japanese acknowledge what happened," he said.

"The Australian Government should also apologise. They were complicit in covering up the atrocities that occurred at Sandakan."

- Bernama