Labour's acting leader David Parker says he believes Nicky Hager has a journalist's right to protect his sources and questioned whether a 10-hour search of Hager's home amounted to intimidation of the media.
Mr Parker said while he respected the independence of the police, it was crucial journalists were not forced to reveal their sources and police needed to tread carefully to ensure those rights are not breached. The Evidence Act gives journalists rights to protect information that may reveal their sources.
"While we respect the police's independence we are concerned that an arm of the state appears to be being used against Mr Hager while nothing appears to be being done about the wrongdoing he exposed. A 10-hour search of their family home would be harrowing for anyone. Nicky Hager was doing that the fourth estate ought to do and Police need to take care to protect his rights and to avoid the appearance of intimidating the media."
The police searched Hager's home last week looking for information on the leaker dubbed RawShark who had provided him with hacked emails and social media messages between WhaleOil blogger Cameron Slater and his acquaintances.
Those emails formed the basis of Hager's Dirty Politics book, released before the election.
Slater laid a complain with police over the hacking and the search was part of the investigation into that.
Prime Minister John Key said it was up to police to pursue the case as they considered appropriate and the Government could not get involved.
"It's appropriate they take the steps they deem necessary but wholly inappropriate for any politician to get involved."
Asked if he believed the law adequately protected people in the position of whistle blowers, he said he didn't have advice on that.
"In the end people make their own calls and take own steps, but I haven't looked into that."
Mr Parker said Hager's book had revealed serious alleged wrongdoings and resulted in a probe into whether former Justice Minister Judith Collins was involved in undermining the Serious Fraud Office and whether the Prime Minister's office was involved in misuse of power in its oversight of Official Information Act requests.
Mr Parker said there was a mounting number of cases in which the police were called in to investigate media - including searches of media offices after Mr Key's conversation with then Act leader John Banks was recorded during the 'teapot tapes' saga and demanding the NBR hand over documents on South Canterbury Finance.
By Claire Trevett of the New Zealand Herald
