Journalist Nicky Hager is putting pressure on Westpac Bank to reveal why it shared his private account details with the police.

Photo: RNZ / Alexander Robertson

The search last October was part of a police investigation into the hacking of blogger Cameron Slater's computer.

The information was gathered by detectives investigating the hacking of blogger Cameron Slater's computer a year ago. The bank gave the information without any court order.

Mr Hager said today he was seeking a "full and frank disclosure" of the extent of the breach from Westpac.

He said 10 months of banking transactions from all of his accounts were handed over to the police without an order.

Over the weekend, Mr Hager said he still banks with Westpac.

The legality of a police search of Nicky Hager's house as part of the investigation into the hacking was challenged in a High Court hearing earlier this year.

The court has not yet released its decision.