Indonesia has convened an unprecedented two-day discussion of anti-communist massacres in 1965-66 that brings together survivors and representatives of the military which is blamed for orchestrating the atrocities.

There were scuffles Monday between protesters who oppose the conference and police outside the tightly guarded venue, in a sign of the deep divisions within Indonesia over what rights group say was one of the worst atrocities of the last century.

Researchers estimate half a million people were killed in the attacks on communists and sympathizers.

But the conference has the backing of government figures and was opened by the Cabinet minister in charge of security and political affairs Luhut Pandjaitan.

He says the country should come to terms with its past but added the death toll has been exaggerated.