The Department of Conservation is being urged to rethink its about-turn on a mining company's application to take ironsand from the Taranaki seabed.
DoC says Trans-Tasman Resources has listened to its concerns about its mining proposal, and has submitted a modified application that DoC won't oppose.
Green MP Gareth Hughes accepted a 6000-signature petition from Ngati Ruanui in September, and says that level of opposition shouldn't be ignored.
"Kiwis love their marine environment. They don't want to see it ripped up and sold off for an overseas company's profit, meanwhile risking dolphins and whales and fishing."
Trans-Tasman Resources wants to dredge up to 36km offshore, extracting 50 million tonnes of ironsands per year.
Mr Hughes claims DOC isn't being up-front about the company's plans.
"They've signed a confidentiality agreement with the company. They've clearly been working with the company, so the information just won't be out there for New Zealanders to make up their own mind."
Mr Hughes says the mining is experimental and he'll make a submission opposing it in person to the independent decision-making committee.
"I think they've got concerns when it comes to such a large-scale experimental activity. When they look around the world and see states and territories like Australia's Northern Territory, putting a moratorium on this novel activity, they think gee, we should too."