Energy Minister Gerry Brownlee last year controversially started a stocktake of valuable minerals in conservation land protected under Schedule Four of the Crown Minerals Act.
The estimated value of untapped minerals has been put at about $140 billion - about 70 percent of that in the conservation estate.
In his opening statement to Parliament today, Mr Key said that a discussion paper on potential changes to land covered under the schedule would recommend that some land be removed and that other areas be added.
"Notwithstanding the public consultation process, it is my expectation that the Government will act on at least some of these recommendations and make significant changes to Schedule 4," Mr Key said.
"This is because new mining on Crown land has the potential to increase economic growth and create jobs." He said mining on conservation land would have to meet strict environmental tests.
"There is ... extraordinary economic potential in the mineral estate residing in Crown-owned land." As a sweetener Mr Key also announced a new Conservation Fund which could get some of its revenue from mining operations on Crown land.
The fund would resource conservation projects.
Green Party co-leader Metiria Turei said that the decision was terrible for New Zealand.
"He's going to try sell off the conservation land to international mining interests and expect that the country will be satisfied with a small conservation fund," she said.
"He's going to cause enormous damage to our tourism industry, he's going to radically affect our biodiversity values in this country which are already at serious risk, and for very little value. Because most of our economic value in the conservation estate is in its natural resources, its forests, its clean waters not in the mineral wealth."
Mr Key said New Zealand needed to use its resources.
"At the moment less than one one-hundreth of one percent is currently being mined. We think there is much greater capability and capacity than that," he told reporters.
At the weekend Reserve Bank Governor Alan Bollard said the Government's goal of catching up with Australia's growth and wage rates was unrealistic and it should focus more on how it could benefit from its bigger neighbour's wealth.
Mr Key today said Dr Bollard had highlighted the importance of minerals to Australia's economy.
"Well, Alan Bollard might be satisfied with the crumbs off Australia's table, I want the entre, the main course and the dessert." Mr Brownlee would not say how much land would be taken off the schedule.
"We have indicated what we think the gross potential value of minerals in New Zealand is. Their recovered value to the economy is another thing, we will just progress that slowly," he told reporters.
"We do think though it is a significant opportunity for the country and we have been very cautious it will take some years to develop. Conservation values are very important to all New Zealanders and that is why we are going through the exercise of having public consultation over anything we might do with schedule four."
Environmental lobby group EDS (Environmental Defence Society) responded cautiously to the announcement.
"We have still to see exactly what the government proposes when it releases a discussion paper on mining later this month or early next," says EDS Chairman Gary Taylor.
"Our expectation is that government will call for public comment on its proposed changes to Schedule 4 of the Crown Minerals Act. So this is presumably not a done deal, but one in which minds are still open to public feedback.
"EDS does not oppose mining on all Crown owned conservation land. It's a question of limiting mining to lower value areas for nature conservation and continuing to protect higher value areas. So let's see the detail of what is proposed and assess at that time whether it's reasonable or not."
Mr Taylor noted Mr Key had said some areas of conservation land not currently protected by Schedule 4 might be afforded that protection, and he said that demonstrated the review was not just "one-way traffic".
Mr Key had also announced a proposed Conservation Fund from royalties on Crown minerals.
"Provided it is new, additional money for conservation, and not a replacement for cut baseline funding, it is a good idea. But it must be designed in such a way that it doesn't create perverse incentives for decision-makers to lower environmental standards," Mr Taylor said.
"Finally, if more Crown land is to be opened up to mining we will be relying on the Resource Management Act to ensure that it's undertaken in an environmentally acceptable way. So further weakening of the RMA should not be contemplated."
