Mr Key also backed Ms Collins' version of events over her role in Slater's online persecution of public servant Simon Pleasants who he believed leaked details of Bill English's accommodation allowance to Labour in 2009.
Ms Collins last week confirmed she had given Mr Pleasants' name to Slater but over the weekend changed her story, saying she gave Slater only Mr Pleasants' job title.
Public Service Association (PSA) acting national secretary Glenn Barclay said: "Minister Collins must take responsibility for her actions and resign. Her behaviour falls well below what is expected of our leaders."
Labour leader David Cunliffe.
Labour Leader David Cunliffe said Mr Key should fire Ms Collins, "because she has acted in a way that is unbecoming and unfit" for a minister.
Ms Collins' office did not respond to the Herald's calls yesterday.
But Security Intelligence Service (SIS) director Rebecca Kitteridge last night backed Mr Key's version of events around the release of information about former Labour leader Phil Goff's briefing from former SIS boss Warren Tucker on Israeli agents in Christchurch.
In the book Hager quotes from emails exchanged between Slater and his friend Aaron Bhatnagar where Slater indicated he expected to receive documents under the Official Information Act contradicting Mr Goff's statements that he did not receive a briefing from Mr Tucker.
Hager and Mr Goff claim Slater received help from the Prime Minister's office to draft his request for the documents and that Mr Key's office expedited their release.
A spokesman for Ms Kitteridge last night said the service's director was "responsible for NZ SIS Official Information Act responses and made the decision to release and what to release in this case".
"Under the no-surprises convention the director or a representative would normally inform the minister's office about what is being released under the OIA."
