The final stage of a bill to increase the threshold of pay equity claims is expected to pass in Parliament.

It'll extinguish 33 active claims, requiring them to re-start under the new model - with the changes expected to impact hundreds of thousands of workers.

This bill has been met with outrage from unions and the Opposition - describing it as a 'dark day for women'. 

Newstalk ZB political editor Jason Walls weighed in on the bill's progress.

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