The chief ombudsman has sided with the government over not releasing a 33-page coalition document, in a provisional decision.
Chief Ombudsman Peter Boshier told the Newsroom website he was satisfied the information was not used by Jacinda Ardern in her role as Prime Minister and was held "solely in her capacity as leader of the New Zealand Labour Party".
But he was considering comments from both sides before he released his final decision.
The provisional decision was released to Newsroom as one of the organisations involved in the complaint.
Ms Ardern said the decision was based around whether the papers were considered official documents.
"That's the question for the ombudsman, that's obviously the decision he's making.
"As I've said, the things we agreed as a coalition are the things we put into the public domain, and that's as it should be.
"As I have traversed a number of times before, there were elements of those discussions that were never finalised, never resolved - they are things that we may never pursue.
"The things that we pursue, we will make public."
National Party leader Bill English said the government should release the document because of the high level of public interest in it.
"A fully transparent government would not be hiding behind the ombudsman, they would be releasing it.
"There is strong public interest in [the document] and they have heightened that by refusing to release it."
Mr Boshier said it was regrettable that Newsroom decided to publish his provisional decision.
"The law requires me to conduct my investigations in private.
"I want to do a thorough job on this investigation. Any suggestion that I have reached a conclusion on this issue is premature."
Mr Boshier said ombudsmen's investigations followed a pattern.
"As with all cases, I investigate, form a provisional opinion and then seek the views of the people who have requested the information.
"In this particular case, I received the requesters' comments last night and I plan to consider their points carefully before I issue a final opinion."
In a statement, Newsroom said the provisional opinion it received was not labelled as confidential and it was not asked to keep the document private pending the release of the final decision.
Newsroom said it sought and received advice from the Ombudsman's Office that there were no restrictions on the publication of the details of a provisional opinion.