Maōri Party co-leader Debbie Ngarewa-Packer's first Members' Bill seeks to ban seabed mining in New Zealand waters and withdraw existing consents.
It is fiercely opposed by mining company Trans-Tasman Resources, which is seeking consents to mine 50 million tonnes a year of iron-sand offshore from Pātea in the South Taranaki Bight.
The New Zealand Supreme Court, meanwhile, is considering whether to uphold an Appeal Court decision which backed a High Court decision declining the consents.
Ngarewa-Packer announced she was putting her Prohibition on Seabed Mining Legislation Amendment Bill in the ballot on March 10. She and her Ngāti Ruanui iwi have been leaders in a campaign against Trans-Tasman's mining proposal, backed by Ngā Rauru, Kiwis Against Seabed Mining, Greenpeace and other iwi and fishing interests.
Allowing Trans-Tasman Resources to mine up to 50 million tonnes of iron-sand a year for 35 years would destroy entire ecosystems and be an environmental disaster, she said.