Winston Peters has defended his party's last-minute decision to block Treaty settlement signings, and labelled the upset Māori Party "hysterical".
All parties had agreed to pass the Bills during extended hours at Parliament this Friday, but at the last minute New Zealand First refused to do it that way, which now means the settlements can't be signed.
Mr Peters' party had previously pledged support for the Taranaki and Te Atiawa Bills, but he's now changed his mind.
"There's one Bill that says that the land belonging to this small group over here will go to the whole iwi. That's wrong in Māori law, that's wrong in our law, and it's a wrong that we should stop."
The blow brought Māori Party co-leader Marama Fox to tears, saying some iwi members have waited 30 years to bring the settlements to Parliament.
"This is their day when these Bills will be passed into law, and it now has to be scrapped because of this stunt," she said.
"It is two days away and those people have had to change their plans and we are absolutely appalled. It is nothing but a stunt."
But Mr Peters dismissed that as "hysterical".
"They think they can ram this down the throat of Parliament by some arrangement outside of Parliament," he said. "That's not the way our democracy works."
He says the vote could still go ahead as planned on Friday, but all MPs would need to be in the House to do it.
With so few remaining sitting weeks left in 2016, Treaty of Waitangi Negotiations Minister Chris Finlayson says it might not be possible to pass all the settlements this year.
Ms Fox says thousands of dollars had been spent by iwi to make arrangements to come to Wellington, as well as catering plans at Parliament for the celebration.
"It is nothing but a stunt by New Zealand First to disrupt the business of the House of Parliament. It is embarrassing and all of those iwi should be sending their bills straight to the New Zealand First camp."