The Government is believed to be planning to reduce the amount of mining it will consider on conservation land.
Radio New Zealand understands a proposal due to go to Cabinet on Monday will reduce the amount of land which could be opened to mining.
An independent report has found $140 billion worth of precious metals lie under the earth, but much is in land barred to mining by Section four of the Crown Minerals Act.
A report to Cabinet was to propose opening about one seventh of this to mining, but private polling has indicated too much mining of conservation land would be politically unpopular.
The Cabinet paper will now reaffirm that some conservation land could be mined, but the area will be reduced.