Police apologise to Nicky Hager for 2014 house raid

Author and investigative journalist Nicky Hager says an apology from New Zealand Police for a raid on his house after Dirty Politics was released was "surprisingly good".

In a sit-down interview with Newshub, Mr Hager said he's amazed Police admitted "all the main breaches".

"When they finally admitted that everything they had done, practically, was against the law - that they shouldn't have done it and they won't do it again - it blew me away.  I wasn't expecting to get there but we did", Mr Hager said.

"We had 11 hours of cops here wading through all our family stuff. It was a comprehensive search like it was murder scene and all of that has been found to be unlawful now."

He said the raid had impacted the willingness of other sources to come forward.

"What I'm hoping this decision will do is that people who've got really important information that matters to the public and matters in big issues won't be too scared to give it to us. That's what really matters, and we couldn't have got a better result for that," Mr Hager told Newshub.

The New Zealand Police issued the extraordinary apology to Mr Hager for a raid on his house in 2014.

The High Court ruled the 10-hour search of Mr Hager's home was "fundamentally unlawful" in 2015.

Mr Hager had just published his work Dirty Politics. The book used hacked messages sent by Whale Oil blogger Cameron Slater on Gmail and Facebook to allege National was using right-wing blogs to attack opponents.

In a settlement on Tuesday, New Zealand Police accepted it attempted to breach Mr Hager's journalistic privilege and that it did not have reasonable grounds for the search.

Mr Hager will receive a pay-out for legal costs and damages as part of the settlement.

In the apology, NZ Police Association acknowledged it should have sought a production order when it sought ten months of Mr Hager's banking transactions.

The Police apology also says the search warrant obtained to search Mr Hager's home should have raised and addressed concerns around journalistic privilege.

"Police failed to mention in their application for the search warrant that they sought information to identify one of Mr Hager's confidential sources and failed to mention that Mr Hager was a journalist who could claim journalistic privilege," Police's apology says.

Police acknowledged Mr Hager was right to expect his confidential sources would be kept private.

The amount of damages paid by Police has been kept under wraps.

Police Minister Stuart Nash didn't have much to say about the case on Tuesday morning.

"It's purely an operational decision. It's purely a decision between the police, Mr Hager and the courts," he told media.

When asked whether he could guarantee the same thing wouldn't happen again, Mr Nash said that's not up to him.

"It's up for the Police to determine how to best keep our communities safe."

Simon Bridges agreed it is a police matter.

"If the police have stuffed up and they got the law wrong, this is for the police to wear."

When asked whether Police had felt political pressure to investigate Mr Hager, Mr Bridges said "I'm sure that's not right".

Professor Ursula Cheer of Canterbury University law school said Police must allow journalists to claim source confidentiality before carrying out a search.

"This is a vital win for journalists, their sources and freedom of expression, both nationally and internationally," she said.