Journalist Nicky Hager will not say whether he plans to sue Westpac bank over the release of his financial information to the police.
Court documents released to the news website Scoop show the police asked for and were given the information without any court order while they were preparing to raid Mr Hager's house.
The search last October was part of a police investigation into the hacking of blogger Cameron Slater's computer.
Information from Mr Slater's computer was published in Mr Hager's book, Dirty Politics.
Mr Hager challenged the legality of the search in a High Court hearing earlier this year. The court has not yet released its decision.
The released court files show police requested detailed information about Mr Hager from a range of organisations.
Those organisations included Spark, Vodafone, Jetstar, Air New Zealand, TradeMe and "16 bank contacts".
The documents reveal that most of the organisations declined the request.
However, Westpac handed over detailed information, including bank statements.
The police can use a production order from the courts to force organisations to provide private information if they have reasonable grounds to believe a crime has been committed, and if the documents would provide them with evidence of that crime.
In an affidavit, one of the police investigators, Detective Inspector Dave Lynch, said the request was to "ascertain any travel movements that may have been able to be linked to [Mr Hager] as well as assessing whether or not he was generating income from the proceeds of the book that could be considered for proceeds of crime action".
In a further affidavit, he said the request was also to work out whether Mr Hager had paid for any of the information from Mr Slater's computer.
However, in submissions to the court, Mr Hager's lawyers said the police request was unreasonable.
"The suggestion that the bank records might disclose payments to the source or otherwise disclose some other yet undetected offence was nothing more than speculation."
The police also lacked any reasonable grounds to believe that Mr Hager had even committed an offence, his lawyers said.
"This was done without obtaining any production orders and in circumstances where production orders would not have been available."
Mr Hager told Radio New Zealand he still banked with Westpac, but would not comment further.
His lawyer, Felix Geiringer, would also not comment on whether Mr Hager intended to take the bank to court.
However, due to legal reasons, Mr Hager could not act anyway unless the court also published the original Westpac documents, which were on the court file but were yet to be released, Mr Geiringer said.
The court documents that were released also revealed that police did not even attempt to interview Mr Hager prior to the 10-hour raid.
The police had considered interviewing Mr Hager, who they considered to be a witness, as part of their investigation, the documents said.
However, they went ahead with the search without doing so.
They also never applied for remote access to Mr Hager's phone or email, despite also identifying that as a possible line of investigation.