A mining company is defending its plan to build a 6.8km tunnel under conservation land in the Coromandel to mine gold.
Anti-mining group Coromandel Watchdog claims the plan will threaten a critically endangered frog and erodes the government's promise to protect conservation land from new mines.
OceanaGold spokesperson Kit Wilson said the company believed it could mine gold in the area "sensitively and respectfully using proven underground methods".
"We know that the area is home to a number of important species and we understand how important this ecosystem is. Studies by independent experts will provide us with the information we need to determine how it could be possible to tunnel or mine under this area."
He said OceanaGold had a mining permit for the activities but had not yet applied for resource consents from the council.
"We will undertake significant, detailed studies before we apply for resource consents. We will undertake detailed investigations and consultation to understand cultural, social and environmental values."
He said the tunnel would be between 150m and 400m underground.
Coromandel Watchdog spokesperson Augusta Macassey-Pickard said the critically endangered Archey's frog, which lives in the forest, would still be at risk from the impacts of blasting.
"Blasting underground is hugely traumatising. It's frightening, it has really significant impacts. Why on earth would we be letting this happen in one of the few places this precious little creature is found?"
She said it was the first effort for mining on DOC land in the Coromandel in more than 40 years.
Macassey-Pickard said OceanaGold had quietly released the plan and said it should have been better publicised.
"This project is clearly mining by stealth, it's undermining conservation land while the government breaks their promise to protect it."
Energy Minister Megan Woods' office did not respond to a request for comment.
Wilson said the resource consent process would allow everyone to have a say on the plan.
"This engagement includes the development of consultation documents, which we have made publicly available on our website and at our information shop in Waihi's main street."
Macassey-Pickard said Coromandel Watchdog would formally oppose the plan and support families in the areas who were concerned.
"We will take every opportunity to fight this development and let people who love the Hauraki forests know what is happening. If DOC and the government will not protect these precious places we have to try our best."