Key Points:

Prime Minister John Key has put most of his assets into a blind trust and says it is "so blind I haven't got a clue what's in it".

Mr Key, whose personal wealth is estimated at $50 million, said he set up the trust before he was sworn in as Prime Minister last year.

In a blind trust, a person hands full discretion over the assets within it to somebody else. It is often used when people want to avoid the perception of having a conflict of interest.

Mr Key first talked about setting up a blind trust last year after controversy arose about his TranzRail shares. He subsequently said a condition of his trust would probably be that it would not buy local shares.

But a spokeswoman yesterday said he had not gone through with this, and the only condition he had given was that the trust was to be "managed conservatively". The spokeswoman said that as Mr Key had no idea of what the trust was investing in, it did not matter whether it was in New Zealand or not.

Mr Key said the only assets that hadn't been transferred into the trust were "real assets", like his houses in Parnell, Omaha Beach and Hawaii.

He also said share options he gained while working for Merrill Lynch (now owned by the Bank of America) could not be transferred and would be declared on the Register of Pecuniary Interests at Parliament, as they have been previously.

He also said there was "ownership of a very small company" called Jackson Mining "which I'll probably sell at some point".

Former Prime Minister Helen Clark had a blind trust and outgoing United States President George W. Bush this week said he was convinced his personal financial accounts had lost money in the nation's financial collapse.

In an interview with Larry King, Mr Bush said he had last spoken to the trustees eight years ago and had "no earthly idea" how much he and First Lady Laura Bush had lost.