Whaleoil blogger Cameron Slater has hit back at Nicky Hager by publishing the "biggest lies" he claims are in his new book.
Mr Slater alleges one of the "lies" in Mr Hager's book Dirty Politics is the claim that John Key's office provided him with information about Phil Goff to humiliate him during the 2011 election campaign.
SIS director Warren Tucker released a note under the Official Information Act to Mr Slater, which claimed that Mr Goff was shown a document relating to an investigation into the activities of a group of Israelis after the Christchurch earthquake.
But Mr Goff, who was the leader of the Labour Party at the time, said Mr Tucker was wrong and he had never been shown the document.
Mr Goff also raised questions about how a right-wing blogger had asked the SIS for a confidential document about a briefing he had with the spy agency, suggesting the National Party had played a hand in Mr Slater's Official Information Act request.
Mr Hager claims in his book that it was the Prime Minister's office who tipped off Mr Slater not the SIS.
"Given that it was highly political SIS business, there seems no doubt that John Key knew what was happening, approved it and had his staff liaise with Slater about the release," he wrote.
Mr Slater said this was a "big lie", saying the Prime Minister and the Prime Minister's office had not told him about Mr Goff's briefing from the SIS.
The Prime Minister says Mr Hager's allegations are unfounded.