Dutch ambassador to Indonesia Tjeerd de Zwaan apologised for the "excesses committed by Dutch forces" between 1945 and Indonesia's independence in 1949.

A UN report at the time condemned the killings as deliberate and ruthless.

"Sometimes it is very important to be able to look back in order to be able to look one another straight in the eyes and be able to move forward together - and that of course is what this public apology and ceremony is all about," he said.