Huge areas of conservation land - including on the West Coast and in the Coromandel - could be off-limits to new mines under a new direction signalled by Conservation Minister Eugenie Sage.
The announcement has raised concerns from the mining industry, which says it could cut jobs in regional New Zealand.
While stressing that it is not a "ban", Sage said she was looking into mechanisms that would achieve that.
"New Zealanders expect that protected lands are places where nature can thrive. They don't expect to see bulldozers and diggers digging up native forests that are protected for conservation."
There is currently a review of stewardship land, which includes over 2.5 million hectares and makes up 30 per cent of conservation land. The review will look to reclassify appropriate tracts of land into conservation estates or land for productive purposes.
One way to protect all conservation lands would be to bring them under Schedule Four of the Crown Minerals Act, which provides protection for areas including national parks, wilderness areas and wildlife sanctuaries.
Some conservation areas have been opened up to mining, while others are the subject of proposals, such as the Te Kuha coal mine proposal near Westport.
A small portion of the 100ha proposal is on conservation land, and a Forest & Bird spokeswoman said the Government's new conservation direction could stop the mine from going ahead.
She added that she hoped it would spell the end for new gold mining prospects in the Coromandel Forest Park, which provides habitat for the critically endangered Archey's Frog.
Opposition leader Bill English expressed concerns.
"They need to make sure that this ban, which covers all conservation land, doesn't have a disproportionate impact on job prospects on, say, the West Coast, where there's always been a pipeline of propositions for mining on lower-value conservation land."
Chris Baker, chief executive for Straterra, which advocates for the mining industry, said the minister's comments "have come out of the blue".
"If it is as it reads, then that's a pretty significant step in terms of where potential regional development and jobs might come from. How are they going to reconcile those objectives?
"We're seeking more information so we understand what the intention is."
Sage said the Government did not want to leave miners out of a job.
"Places like the West Coast and Coromandel have diversified their economies on the back of their stunning natural beauty and landscapes. This Government is committed to helping workers in these regions make a just transition from mining.
"Obviously there will be consultation with key stakeholders, including the mining industry."
Minister for Rural Communities Damien O'Connor said stopping mining on conservation land would not have a large impact on jobs, as current mines would not be closed down.
"Most of the jobs have gone in the mining industry. There are still mines existing, and those will continue. The issue is whether there is any major growth in the future."
He said if a future mine was proposed for conservation land,"then it's unlikely it will go ahead".