The Government is not racing into a decision about whether to mine areas of conservation land, Energy and Resources Minister Gerry Brownlee says.
His comments come after up to 40,000 people, including actresses Lucy Lawless and Robyn Malcolm, marched through central Auckland on Saturday protesting against the proposed mining.
The Government has proposed removing some conservation areas from Schedule 4 of the Crown Minerals Act, which protects them from mining.
Those areas include parts of Great Barrier Island, the Coromandel and Paparoa National Park.
The Government has extended the period for submissions to May 26.
"Rather than just doing something which we could have just gone ahead and done it, we've actually gone out and said to New Zealanders tell us what you think," Mr Brownlee told TVNZ's Breakfast show.
The Government also needed extra time to consult with iwi and community groups, he said.
Mr Brownlee had not yet seen any of the submissions.
"In the end we need to look at the widest possible range of considerations and we'll do that in the best interests of the country.
"We're not racing head-long into this."
He would not be drawn on whether he supported the mining of Schedule 4 land.
"Our obligation as a government is to try and grow the economy of New Zealand, so we're looking at range of things across the economy that might be possible. This is one small part of it."
Last week, Parliamentary Commissioner for the Environment Jan Wright said there wasn't enough information available to decide on whether mining should be allowed in some protected areas.
There was a lack of information available about the conservation value of the land, the benefit of mining it and problems raised by the joint access approval, she said.