Around 700,000 people did not complete the 2018 Census, according to Statistics New Zealand.
Chief executive Liz MacPherson has finally given the country's politicians more information - and National MP Nick Smith claims the total number of partial respondents and non-respondents totals 700,000.
More than a year since the Census was completed, MacPherson wrote a letter to MPs with more information - but still not the full Census figures.
She'll be releasing more Census data on April 29th but did reveal that the number of partial responses were up from two percent in the 2013 Census to five percent in 2018.
That means that around 240,000 people only partially completed the Census and 460,000 New Zealanders did not complete it - if Smith's total of 700,000 is accurate.
MacPherson felt compelled to respond to Parliament's governance and administration committee, after stonewalling over the number of partially and fully completed responses.
She claims the Ministry needs more time to fully evaluate the data and doesn't want to mislead anyone.
"I have come to the conclusion that the importance of maintaining trust and confidence in the 2018 Census and the official statistics system, outweighs the risk of information about partial responses being misunderstood."
Now the opposition is blasting the Government and calling for another Census.
"It's been like drawing teeth to get information from Statistics New Zealand about the results," Smith - National's State Services spokesperson - said.
Smith says the record low response will not give the Government accurate results, and the problems with Census 2018 are not just the record low response rate - but a doubling in the partial response rate.
That compounds the problems for the State Sector, which relies on hard data.
"We now know over 700,000 people, or one in seven New Zealanders, did not complete Census 2018. This leaves a huge data hole that will create problems for years in allocating tens of billions of dollars in funding for central state services like health and education, as well as affecting electorate numbers and boundaries for Election 2020," Smith said.
Prime Minister Jacinda Ardern yesterday hit back at Smith, pointing out that it was the previous Government that made the decision to move to an online Census - which appears to have been part of the problem with the big drop in responses.
But Smith isn't buying that.
"Stats NZ needs to accept responsibility for the 2018 Census shambles. It cannot blame the funding when it was 36 percent greater than Census 2013 and when this budget was underspent. It cannot blame the digital strategy when Australia successfully delivered its 2016 Census with a 95 percent response rate using a similar strategy."
Smith says Stats NZ botched the delivery of Census 2018 by excessively relying on online responses and providing insufficient neighbourhood backup for others.
He's even calling for consideration to given to deferring the electoral boundary changes for 2020, as well as bringing forward the next Census to 2021.