"At the end of the day, he's not my guy, Cameron Slater ... anyone who knows Cameron Slater knows that he's a force unto himself, and the at the end of the day he gets his information from a whole bunch of things. I'm not here to either defend the guy."
Asked if he respected Slater's work, Mr Key told RNZ: "That's not for me to critique his stuff."
He said social media was "part of the overall media network these days, and I have to deal with those issues like anyone else".
Mr Key said Hager's book had been selective in the emails it drew upon.
"They're based on one perspective and probably a bit out of context and with a whole bunch of assumptions that either aren't correct or are made up, and now can't be backed up."
The book claims Slater was tipped off by the Prime Minister's office to ask the Security Intelligence Service (SIS) for a confidential document about a briefing former Labour Leader Phil Goff had with the spy agency in 2011.
Watch: "We're helping Key get off his high horse"
Mr Key this morning denied Slater's Official Information Act request about the briefing had come across his desk.
He said he would have known about it, but he had not signed off on it.
"They always sign off on things on their own timetable. We've got slightly better processes now, so they'll tell me."
Mr Key also responded to the book's claims a National staffer had accessed confidential donor and member information from a Labour Party website database in 2011.
National's general manager Greg Hamilton has acknowledged a staff member was responsible for exploiting a security vulnerability to access the database.
"The point here was that there was no hacking or anything," Mr Key told RNZ.
"If a left-wing blogger went around and found out that there was a situation where the security had been taken off [the National website] and went and told and told that to, I don't know, someone who works in David Cunliffe's office, would they potentially go and have a look?"
Speaking on TVNZ's Breakfast this morning, Mr Key said: "Yes, of course National talks to right-wing bloggers, of which Cameron Slater is one."
He said Slater attacked the National Party as much as he defended it.
"Of course we try and get messages out there. I'm sure the various Labour leader's offices do the same with the left. Go and look at The Standard, go and look at other left-wing blogs.
"If I didn't have to deal with blogs, my life would be great, but the reality is I get asked lots of questions about them, and half the time I'll go and look at them."
He said Justice Minister Judith Collins had "a strong relationship with Cameron Slater, they always have. They've known each other well".
Mr Key said he did not have a relationship with Slater in the same way.
"You can ask Cameron, he'll tell you that. I talk to David Farrar, because he's our pollster, so I talk to him very regularly. In the case of Cameron, I have very few conversations."
Mr Key had "occasionally" called Slater because he wanted to discuss a particular topic.
He said he did not know Mr Ede had been going through Labour's database.
"I probably should have known, because there was some correspondence between National and Labour that a person had."
National had not "hacked in" to the website, and the site's security had been "left off".
"Jason became aware of that, and he did go and have a look."
Mr Key agreed it was a back-door way into the website.
On RNZ, Mr Key would not say whether it was appropriate for Ms Collins to divulge the name of a public servant, who was thought to have leaked information, to Slater.
"I don't have the details on that on," he said.
When pressed, he would not give a yes or no answer, adding: "People can see that this is a smear campaign by Nicky Hager."
Mr Key said he stood by Ms Collins.
Race to get tighter, grubbier
The election race is getting closer and is set to get grubbier as two polls show National's easy ride to a third term is not such a sure thing - even before the Dirty Politics scandal takes effect.
But with the political firefight over author Nicky Hager's expose of alleged Government dirty tricks intensifying yesterday, election policies such as the Greens' plan to sock the wealthiest New Zealanders with a new top tax rate risk getting lost in the noise.
One News and 3 News issued their first election campaign polls last night, with both showing National down by two points.
The One News-Colmar Brunton poll had National at 50 per cent, while 3 News-Reid research had them at 47.5 per cent. While One News also had Labour down 2 points at 26 per cent, leader David Cunliffe had something to cheer about, with 3 News putting his party 2.3 per cent higher at 29 per cent.
Both polls were conducted in the week before Hager's book was released and in the aftermath of NZ First leader Winston Peters' widely criticised "two wongs" joke. But far from NZ First being hurt, the party's support was up, hitting the 5 per cent MMP threshold, according to One News, and rising within spitting distance to 4.6 per cent, according to 3 News.
The heat is intensifying. Photos / NZ Herald
NZ First's improving fortunes raise the prospect Winston Peters will again have the role of kingmaker after the September 20 election.
The poll results have come as the Government and its blogger allies Cameron Slater and David Farrar ramped up their counter-attack on Hager and his credibility.
Hager is already under pressure over how he came into possession of thousands of emails and other messages the book is based on and which he acknowledges were hacked from the computer of Slater, who write the Whale Oil blog.
Farrar yesterday confirmed to the Herald he would complain to the police about how material used by his polling company found its way into Hager's book. He told the Herald he believed polling scripts were being supplied by an employee to Hager.
Slater yesterday made more forceful claims that the thousands of his emails and other messages which Hager's book is based on were hacked from his computer by Internet Party founder Kim Dotcom. In a post, he linked the hacking of his computer, the burglary of National MP Mark Mitchell's offices, the "theft" of material from Farrar's company and two more burglaries to Mr Dotcom.
Mr Dotcom said Slater's post was "designed to shift focus away from Slater's own dirty dealings on behalf of the National Party".
"I had nothing to do with any alleged hacking. And while we're on the subject, I had nothing to do with Nicky Hager's book, either."
Hager told TVNZ's Q+A programme that Mr Dotcom was "absolutely categorically" not the source of information he had received.
Prime Minister John Key, meanwhile, told reporters that Hager "isn't actually denying he's written a book off stolen material".
He again said he did not plan to look further into the book's central claims that his former staffer Jason Ede covertly accessed Labour's IT systems or that Justice Minister Judith Collins abused her position to pass on information to Slater to fuel his attacks on political opponents.
Mr Key did not wish to know the identity of the staffer National has acknowledged accessed Labour's computers and said that "most of the stuff about Judith Collins has actually been proven to be factually incorrect".
• Check out the full coverage of Hager's book here.
