The Greens, National and ACT are collectively outraged over Labour repeatedly shooting down requests for a briefing on house price forecasting.
Green MP Chlöe Swarbrick, who sits on Parliament's Finance and Expenditure Committee [FEC], has twice sought a briefing from Treasury officials on how it creates its advice on house price forecasting.
She says it's important because in 2020, Treasury predicted a house price fall, which informed Government and Reserve Bank decisions that, instead, saw house prices increase an historic 25 percent in one year.
But Labour members voted down Swarbrick's request - not once, but twice. Labour is traditionally the Green Party's closest ally, but in this case, Swarbrick has the support of right-wing parties National and ACT.
"This shouldn't be partisan. It's about the quality and kind of advice given by officials to inform our central bank and Government's decisions," Swarbrick told Newshub.
"FEC has the parliamentary function to scrutinise this stuff, which makes our democracy healthier and decisions better informed and stress-tested. I'm genuinely perplexed at the unnecessary partisanship from Labour MPs in blocking this en masse."
National MP Nicola Willis says it was a "bit surprising" to be on side with the Greens, but believes the two parties just want greater transparency.
"I think concern about New Zealand's housing situation crosses all political divides. This is an issue that matters to everyone and I think New Zealanders would be pleased to see we can put partisan politics to the side to do what's right," she told Newshub.
"It's actually quite perplexing. What do they have to hide? What is the harm in us better-understanding how officials are forecasting house prices?"
ACT leader David Seymour says Parliament exists as the voice of the people.
"If the Government won't let select committees do their work, they're denying the voices of people who are elected MPs to scrutinise the Government," he told Newshub.
"Frankly, I think this Government has become arrogant. They should realise that Parliament and the voters who elect it are higher than any Government and they deserve scrutiny and they deserve a Government that fronts up to scrutiny."
Finance Minister Grant Robertson says Treasury included information about house price predictions in May's Budget. Post-2022, Treasury expects values to keep rising, but nowhere near as quickly as they have in the past couple of years - from 2.1 percent in 2023 to 2.5 percent in 2025.
Robertson says the FEC has the right to shoot down Swarbrick's request.
"Those are totally decisions for the Finance and Expenditure Committee to make," Robertson told Newshub. "I know that the Treasury is answering a series of questions as a part of the estimates process that cover this material and it was also covered quite significantly in the Budget documents too."
But Seymour says it's those forecasts that need scrutiny.
"The Government that said it would be open and transparent, is denying scrutiny of the most important forecasts being made."
Willis wonders if the Government has something to hide.
"I think Labour MPs need to remember they are there to represent the people, they are there to represent our communities; they're not just there to do the bidding of Government ministers."
But Swarbrick doubts that.
"There's a common practice of MPs in big Government parties (both stripes) not doing stuff in committees unless their ministers wink-wink, nudge-nudge, sign it off. That feels (kind of is) unconstitutional - and exhausting," she wrote on Facebook.
"It stops a whole lot of progress and accountability - even on stuff that should be minor - when one party holds total majority, and their MPs won't jump unless or until the Minister says so."
Labour MP Duncan Webb, chair of the FEC, says committee members have the opportunity to ask oral questions.
"There is ample opportunity for the Opposition to inquire into house price forecasting. So far we have had the Treasury in for examination six times this year, and they will be in again. We have had the Reserve Bank in three times this year and they will be in again soon," he told Newshub.
"Given the extensive opportunity for examination through normal channels, a special briefing was seen as duplicative by the majority of the committee."
Swarbrick isn't giving up.
"I'll put the motion every week until we get the information necessary."