Stats NZ has appointed an independent external investigator to look 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 former marae workers who collected census forms last year.
They claim private data from these forms were photocopied and entered into a database, which they believe was then used to target voters in the Tāmaki Makaurau electorate.
In a statement on Wednesday, Stats NZ chief executive Mark Sowden said Doug Craig of the RDC Group had been appointed to investigate the allegations.
"Mr Craig is an experienced public sector leader and a former State Services Deputy Commissioner, with a background in law, accounting and strategy.
"He has significant experience in implementing large and complex projects and has advised on and led many organisational wide responses to critical incidents of a similar nature.
"Mr Craig is a member of the Public Service Commission's panel of independent reviewers."
Stats NZ is finalising Craig's contract and terms of the investigation.
"We take these allegations very seriously. The findings of Mr Craig's investigation will be shared with NZ Police who are also investigating.
"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 in which it is collected.
"The Minister is aware of the allegations and subsequent investigation."
Police confirmed 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.
