Environment Minister David Parker has proposed a select committee inquiry into seabed mining - a move Te Pāti Māori says is weak and disappointing.
Parker said the inquiry would consider if changes were needed to seabed regulation in New Zealand's domestic zone, looking into risks and benefits of mining.
New Zealand has rights to a large exclusive economic zone (EEZ) extending 200 nautical miles out from the territorial sea, plus an area of the continental shelf, covering about 1.7 million square kilometres. Together, they give New Zealand the fourth-largest maritime territory in the world.
With Labour holding a majority on the select committee, the proposal seems certain to succeed.
It follows the government's backing last year of a moratorium on international seabed mining until science-backed environmental rules could be agreed on.
Parker said that would not affect the domestic rules, but "having backed a conditional moratorium, it is timely to examine our own regulatory settings".
Te Pāti Māori co-leader Debbie Ngarewa-Packer said the party would take part in the inquiry, but it was a cop-out from the government.
"I'm hugely disappointed that Labour is proposing such weak action on seabed mining and refusing to support my Member's Bill which would protect our oceans for future generations," she said.
"Really, really angry and annoyed that they haven't shown the strength and environmental kaupapa that they should have.
"Seabed mining has been consistently rejected in the courts, and across the board by tangata whenua, coastal communities, environmental groups, fishing interests and the public at large. My bill would draw a line in the sand and end costly litigation and uncertainty.
She said it showed Parker understood they had to be seen to be doing something, but given the backing for the international moratorium is "reeks of hypocrisy".
However, Parker said Ngarewa-Packer's bill, which would prohibit domestic seabed mining, would affect previous arrangements and engagement with claimant groups.
"That bill would override existing minerals permits and consents immediately, retrospectively, and without compensation," he said. "That would cut off much of New Zealand's current gas supply, threaten our energy security, and cause considerable reputational damage to the country."
Ngarewa-Packer said that was a red herring, with only one application.
Green MP Eugenie Sage, who also chairs the environment committee, said the party welcomed the inquiry but would prefer faster action in domestic waters.
"We need to put the health of our ocean's habitats and ecosystems ahead of the profits of international mining corporations," she said.
She urged the government to support Ngarewa-Packer's bill at first reading so the matter could be debated, referred to select committee and amended as needed.
"While a Select Committee inquiry will undoubtedly focus MPs' minds on the importance of marine biodiversity and the impacts of mining companies sucking up the seabed, the government has sidestepped a decision to avoid industrial scale exploitation of our ocean floor."
She also called for Labour to support her own member's bill to protect conservation lands from new mining, due for debate next week.