The police raid on investigative journalist Nicky Hager's Wellington home could have a "chilling effect" on the media and future whistleblowers, a court has been told.
Lawyers for Hager are in the High Court at Wellington today arguing that the "extremely invasive" 10-hour search carried out in October 2014 should never have happened.
Hager has sought a judicial review of the way police applied for a search warrant, the subsequent granting of the application, and how the search was carried out.
The raid took place in the aftermath of the release of Hager's book, Dirty Politics, which was based on information taken from Whale Oil blogger Cameron Slater's emails and online communications.
The information was given to Hager by an anonymous hacker and the police investigation into the alleged hacking of Slater's computer is ongoing.
Hager's lawyer Julian Miles QC told the court that his client, as a journalist, has a presumptive right under the law to keep his sources secret and that that is a fundamental part of the democratic process.
"None of these principle issues...appear to have concerned the police when they decided to launch the application for the warrant," Mr Miles said.
Had the police properly considered Hager's interests, and those of his sources and the public, "they would not have conducted the search", Hager's lawyers said in their written submissions to the court.
"The interests at stake in permitting Mr Hager to protect the identity of his confidential informant are high. The fact the search would violate the privilege of other confidential informants makes these interests even higher."
Police were aware some of the information they were likely to come across during the search would be subject to journalistic privilege, but they went ahead anyway, he said.
Hager's house was turned "upside down" during the search and confidential documents relating to his previous work and investigations were potentially caught up in it.
Mr Miles said the actions of police could compromise not just Hager's future investigations, but those of other journalists.
If police are able to carry out raids or searches on journalists and force them to reveal information, "that would have a chilling effect on future informants", Mr Miles said.
It would send a signal to those would-be informants that their identity could be at risk, he said.
The court was also told that other journalists knew the identity of the alleged hacker, but police chose not to search the New Zealand Herald, Fairfax or TV3.
"They chose the easiest target," Mr Miles said.
The hearing before Justice Denis Clifford is set down for three days.