The document she gave to health officials argued for tobacco tax cuts, and promoted the idea that "nicotine is as harmful as caffeine" and argued that Labour's smokefree generation policy was "nanny state nonsense".
Chief Ombudsman Peter Boshier began an investigation after receiving a complaint from RNZ about the Associate Minister's refusal to release information on who wrote it.
Boshier said after the investigation began Costello clarified the request was refused under 18(g) of the Official Information Act, because she didn't know who wrote or collated the notes.
The minister said she only received a hard copy of the notes that were placed on her desk and that her staff told her they didn't know who authored the notes.
Boshier concluded Costello made reasonable efforts to try to determine who wrote or compiled the notes, and it was open to her to refuse the request on the basis she didn't hold information about who authored the notes.
But he was concerned the associate minister wasn't able to produce any records about the source of the notes.
In a statement Boshier said he taken the "rare step" of notifying the Chief Archivist over the record-keeping issues.
The associate minister's failure to make reference to any OIA withholding ground when she refused the request was contrary to law, he said.
The document
In December 2023, RNZ asked the newly appointed minister Costello to release all documents relating to tobacco and vaping policy under the Official Information Act.
She refused to hand over any information at all.
RNZ had been leaked a document on tobacco policy that her office had sent to health officials which was highly political in tone and content. It described the previous Labour government's smokefree policies as "ideological nonsense that no other country had been stupid enough to implement" and said New Zealanders were "guinea pigs in their radical policy experiment".
In February, Labour asked in a written parliamentary question who wrote the document, and Costello responded: "There was no specific document written. A range of information was provided to officials, including material like Hansard reports, the Coalition Agreement and previous NZ First policy positions."
RNZ sought an investigation by the Chief Ombudsman, who ruled Costello had acted "contrary to law" in withholding the information and forced her to apologise and release the documents.
In response to RNZ's OIA request, Costello acknowledged the document existed but has said she did not know who wrote it - only that the author did not work in her office.
"The document you have referred to was not generated or collated by any members of my office and was only received as a hard copy on December 6," she wrote.
She said she still did not know who wrote the document or even who gave it to her.
RNZ also asked Costello whether she could rule out tobacco industry involvement in the mystery document if she did not know its author, and also why she would give a document to officials without knowing its origin.
She did not address specific questions but said she had no links to the tobacco industry and no involvement with it.
