The Department of Conservation had also asked that its potential funding contribution also be kept confidential, he said.
DoC director of partnerships national support David Talbot confirmed to the Herald it had also been asked for money and was still considering an application to its Nature Heritage Fund for a contribution towards their purchase of the headland.
The New Zealand Coastal Trust purchased the 30ha piece of land in Wainuiototo Bay for $2.15 million last December.
Under the trust's ownership, the land will not be developed.
The property was sold by tender by Colliers on behalf of receivers appointed by the Bank of New Zealand after the former owner, Galt Nominees, itself owned by businessman George Kerr, defaulted on a mortgage.
At the time of the land being purchased, the Environmental Defence Society, which co-ordinated the offer, said a smaller number of committed individuals had agreed to underwrite the offer pending resolution of grant applications to funding entities.
The rest of the money had also been raised in less than four weeks through partner groups, the local community and donations made to a Givealittle page.
The New Zealand Coastal Trust has been approached for comment.