The New South Wales Premier says a tribunal may be set up to work out how to repay Aboriginal workers whose wages were paid into government trust funds, but never given to them.

A secret policy document says the workers were treated like "Nazi slaves".

The four-year-old policy document likens the trust funds to schemes operated by private companies using slave labour in Nazi Germany.

The workers' wages were paid into government trust funds and never returned to them.

Speaking about the issue for the second time in recent weeks, Premier Bob Carr has emphasised that tracking down those to whom funds are owed may be virtually impossible.

"The difficulty here is that there are no records - the records have vanished," Mr Carr said.

"That means we can't hand out public money wholus bolus."

Mr Carr says he is deciding whether to set up a tribunal to examine people's claims to the money, but applicants would need to provide solid proof of their entitlements.