Changes to Māori marine title have gone before the justice select committee, with one submitter saying the Bill is based on racist myth.
The changes to the Marine and Coastal Area Act would make it harder for Māori to make customary claims on coastlines.
Section 58 of the Marine and Coastal Area Act 2011 requires an applicant group to prove they have exclusively used and occupied an area from 1840 to the present day, without substantial interruption, before they are granted Customary Marine Title (CMT).
That threshold for CMT was eased after a decision by the Court of Appeal which found groups only needed to show they had enough control over the area that they could keep others from using it, and situations where the law itself had preventing them from doing so could be ignored - that decision is back before the Supreme Court on 4 November.
Earlier this year, Justice Minister Paul Goldsmith announced the government would introduce legislation to overturn the Court of Appeals decision - and amend section 58 "to make clear Parliament's original intent".
This was supported by Hobson's Pledge leader Don Brash, who told the committee the courts had reinterpreted that intent.
"We feel strongly supportive of this Bill as it intends to amend the original Marine and Coastal Area Act. Having said that if we had a choice we'd go back to the Foreshore and Seabed Act in 2004 where the Crown owns the foreshore and seabed on behalf of all New Zealanders, but that isn't on the table," he said.
Victoria University law lecturer Luke Fitzmaurice-Brown said the Bill was based on the racist myth that upholding Māori coastal rights meant people would be unable to access public beaches.
"That has never been true and the current law makes that very clear," he said.
CMT cannot be sold and had no effect on public access, fishing or other recreational activities, but grants rights over resource consents, conservation, consultation rights over marine mammal watching and coastal policy, and ownership of various minerals and protected objects.
Fitzmaurice-Brown told the committee changes to the law were "deeply reckless" and asked for the Bill to be withdrawn.
"Through this Bill and other Bills this current government, you as many members of this committee, are unpicking the constitutional fabric of this country one thread at a time and in my view that is deeply reckless."
Māori groups whose cases for CMT had already been decided in the courts - or had been decided and were under appeal - would remain unchanged
However, cases that were still live before the courts or were undetermined would need to meet the higher threshold set by the government's new legislation.
In September, the Waitangi Tribunal recommended the government halt its current efforts to amend the Marine and Coastal Area Act.
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