A Burmese refugee living in Australia says he committed 24 executions while working undercover for the Burmese military regime and says he was involved in at least another 100 murders.

Htoo Htoo Han, now an Australian citizen, says he performed the executions during the 1988 anti-government uprising that swept Burma, resulting in thousands of deaths.

Han says he worked as an undercover officer in Burmese military intelligence from 1987 until 1992, leading a group whose main role was to identify targets and kill them.

"I did it, I am a war criminal," he said.

"For so long I have lived like an animal.

"Now I want to release what I carry inside for 20 years. I want to say sorry to the mothers and fathers of the people I killed."

Han says he chose to approach the media with his story, fearing it might not be told if he went directly to authorities.

The 44-year-old father of three young children says he expects to be dealt with and is ready to turn himself over to Australian authorities.

He says he led a group that infiltrated student groups and masqueraded as protesters.

As leader of the group, he says he was also indirectly involved in at least 100 other murders.

"We destroy them ... destroy means kill," Han said.

He says he killed his victims with a bullet to the back of the head, but is aware of others who were buried alive and their bodies incinerated.

"Just bang, very quick. I don't do torture," he said.

Han has come forward because he says he can no longer live with his guilt.

An Australian citizen for more than a decade, Han says he turned his back on his former Burmese masters before coming to this country, a decision he claims resulted in an attempt on his own life.

Since arriving here he has campaigned widely in Australia against his former government, speaking in schools and using his artistic skills to focus on repression and human rights abuses around the world.

He insists he has not engaged in any criminal activity in Australia.

In 2003, SBS television made a documentary around a campaign he conducted in Australia to raise awareness of human rights abuses in Burma.

Han says he is prepared to face whatever justice he deserves, including a long jail term.

He also acknowledges he may never see his children again, but he hopes they will come to understand what he has done.

"I am prepared for this. I think my wife and kids for sure will cry a lot," he said.

"But in Burma a thousand mothers cry."

Attorney-General Robert McClelland has labelled Han's comments "extremely serious" and says the matter will be assessed by the Australian Federal Police.

"Australia has a strong framework in place for protecting the Australian community from the perpetrators of war crimes, and for ensuring their proper investigation and prosecution," he said in a statement.

AAP