Academics say a Government inquiry into the abuse of children in state care should be expanded to include adults as well.

The Government plans to set up an inquiry focusing on the abuse of children, but a number of experts say that's not enough

New Zealand Centre for Human Rights director Rosslyn Noonan said a full Royal Commission should be launched.

READ MORE: Govt refuses to extend child abuse enquiry to churches, sports clubs

She said the investigation should also cover the experiences of vulnerable adults with disabilities in out-of-home care.

"This is one of the most awful blots on New Zealand's history and we all need to know exactly what happened."

She said the full extent of the abuse is still unknown.

"New Zealanders need to know the scale of the issue because I think actually in the past we have turned a blind eye to what was happening and we could have stopped it much earlier."