The government is facing calls to launch an independent wide-ranging inquiry into claims that Manurewa Marae misused census data to help Te Pāti Māori's election campaign.
The Sunday Star Times was the first to report the accounts of ex-marae workers who collected census forms last year.
They claim private data from the forms was photocopied and entered into a database which they believe was then used to target voters in the Tāmaki Makaurau electorate.
Stats NZ has launched an investigation into the claims. Police have also confimed they received a complaint last week.
Te Pāti Māori president John Tamihere strongly denied the allegations, calling for anyone to produce "hard evidence" and describing "unsubstantiated sources" as unhelpful.
Manurewa Marae chief executive was Te Pāti Māori MP Takutai Tarsh Kemp.
Kemp stepped down from the role after narrowly winning the Tāmaki Makaurau seat last year.
In a statement, Stats NZ chief executive Mark Sowden said the agency had brought in an external party to investigate after receiving the allegations late last week.
"We are taking these allegations very seriously," he said.
"It is paramount that the information collected via census forms or any Stats NZ survey is kept private, secure, and confidential, and that it is only used for the purposes [for] which it is collected."
A spokesperson for Te Pāti Māori said Kemp continued to have the party's "full support and confidence" to continue serving her electorate.
"We unequivocally refute these allegations ... they are baseless and simply untrue," the spokesperson said in a statement.
"As the matter is live before an employment court process, and on legal advice given, no further comment will be made."
The Sunday Star Times also reported that attempts to alert both Stats NZ and the Ministry of Social Development were not followed up.
Statistics Minister Andrew Bayly told RNZ the outcome of the agency's external inquiry would inform "appropriate next steps".
Employment advocate Allan Halse represents a group of ex-marae staff and a whistleblower at the Ministry of Social Development.
He said there needed to be a multi-party inquiry into the entire process "from beginning to end" including the role of government departments.
"All of it could have been avoided," Halse said.
"If the authorities, when they learned what was taking place, had acted, they could've prevented this from continuing."
Taxpayers' Union spokesperson Jordan Williams said the government must hold a public inquiry with the power to compel witnesses and take evidence on oath.
"These allegations are on the most serious end in terms of misuse of census information," Williams said.
"It warrants an independent review to establish both what has happened, and whether agencies have responded with appropriate urgency."
Speaking to reporters on Tuesday afternoon, Labour leader Chris Hipkins said the allegations warranted a "rigourous and very credible" review.
"Filling in your census is a compulsory thing - everybody has to do it - but part of the deal there is that your privacy is very jealously guarded.
"If there's been a breach in that, then they do need to get to the bottom of how that happened ... and make sure it can never happen again."
Back in 2023, the Electoral Commission was investigating concerns over voting at Manurewa Marae.