Energy and Resources Minister Gerry Brownlee has moved to clarify conflicting figures for mining on some conservation land.
Government proposals to open up some conservation land for mining target land on parts of the Coromandel Peninsula and Great Barrier Island in the North Island, and the Inangahua sector of the Paparoa National Park in the South Island.
Mr Brownlee initially said the potential mineral value in Great Barrier Island is about $4.3 billion.
He later acknowledged a lower figure from geologist Richard Barker's report of $1.28 billion, but has now returned to the first estimate.
Mr Brownlee told Morning Report that he had his staff check out the numbers.
He said the higher figure, in a Ministry of Economic Development report, is calculated on a broader range of criteria and encompasses a bigger land mass than was defined in Mr Barker's report.
Mr Brownlee said the lower figure is based on older more limited data.
"In the end ... its a bit like two cooks having an argument over how many dates are in the scones," he said. "Until you get the thing, you don't know."
Asked about his assertion the conservation land of New Zealand that could be mined was the equivalent to a postcard in Eden Park, Mr Brownlee said it was a metaphoric comparison.
He said it refered to a "very small amount of land" which may end up being mined - 500 hectares of 26 million hectares, and the exact area figure had always been clear.
Mr Brownlee said the Government would like to take schedule four designation from approximately 7000 hectares to find out what minerals are available.
"Beyond that, there's a massive process through the (Resource Management Act) before you ever get to mining."
The Labour Party says the Government's mining plan is a shambles.
Party leader Phil Goff says there is still uncertainty about how much of the Great Barrier Island would be affected.
He says mining should focus on the 60% of the country's mineral wealth that is outside protected areas.
But Gerry Brownlee says the Opposition's objections to mining are hypocritical.
He told Parliament that Labour approved 218 permits for mining on the Conservation Estate.
He says that shows Labour was happy for mining to take place on 21,961ha of land, while the government is seeking approval to release a mere 7,058 hectares of the most protected, Schedule Four land.
