A provision in the three waters legislation requiring a 60% vote to repeal its protections against privatisation has been called “unconstitutional and undemocratic” by the National Party.

The provision, adopted by the house during the committee stage debate, means the support of 60% of MPs (or a majority vote at a referendum) will be needed before any future parliament can allow privatisation of the “water entities” set to be created by the law.

“Entrenched provisions are used rarely in New Zealand, for good reason,” said National justice spokesperson Paul Goldsmith.

“Labour and the Greens have now colluded to entrench in law a contentious policy position, without any real debate and while the House was sitting under urgency.”

National’s local government spokesperson Simon Watts said Labour had “used the veil of urgency to ram through an unconstitutional clause to block future changes to a broken bill, which National will repeal and replace”.

He called for the bill to be sent back to the committee to excise “this unconstitutional and undemocratic clause”.