Prime Minister John Key says he is unaware of any details about family shares and assets managed by a blind trust, set up soon after he took office.
A blind trust is often used by politicans to avoid conflicts of interest, and empowers the trustee to make investment decisions without the benefactor's knowledge or authorisation.
Mr Key has faced questions about a central Otago vineyard, Highwater, and whether other shareholders may benefit from his position.
He says he used to have part shares, but they were disposed of when the trust was established in late 2008.
Companies Office records show Mr Key's Highwater shares are now owned by a company called Whitechapel.
One of Whitechapel's two directors is Mr Key's family trust lawyer, Kenneth Grey Whitney.
Whitechapel also owns shares previously held by Mr Key and his wife in two other companies.