JOHN KEY: The Prime Minister the naming of the staffing at the heart of the briefing is "no big deal one way or the other."

The prime minister's office has released the name of the staff member briefed by the SIS over the release of information to WhaleOil blogger Cameron Slater.

A spokeswoman for Prime Minister John Key confirmed former deputy chief of staff Phil de Joux was told by SIS director Warren Tucker under the "no surprises" policy that Slater would be receiving the declassified documents.

Nicky Hager said in his Dirty Politics book that Slater received the response to his Official Information Act request within a week, and quoted Facebook messages suggesting Slater knew what would be in the documents.

He alleged Slater was tipped off by Key's staff to ask for the papers, which embarrassed then-Labour leader Phil Goff who wrongly denied being briefed by the SIS.

Key came under fire after he denied being briefed about the release of the documents to Slater - video footage emerged of Key saying Tucker had discussed the matter with him.

Key later clarified that in that context, briefing the prime minister meant briefing the prime minister's office.

He refused to disclose which of his staff members had been briefed by Tucker, however.

Today Key said he was "comfortable" with the release of de Joux's name, a matter the Ombudsman was investigating.

"The only reason we didn't name names is simply because these people handle sensitive information and in the case of Phil de Joux he now works in the private sector, so it's really just a privacy matter, but it's no big deal one way or the other."

Goff says it was "very hard to believe that material that came from the SIS, the Prime Minister wouldn't have known what his staff was doing about it".

"I know with Helen Clark, anything to do with the SIS she dealt with personally. I can't believe any staff member would leak material from the SIS without ... John Key knowing about it."

Goff said SIS briefings were never released, other than on this occasion.

Labour leader David Cunliffe said Key's initial claims that the details should not be released in order to protect the staff member was not believable.

"This calls into real question whether or not the prime minister knew that this OIA request from Whaleoil was manipulated by the SIS. It's not good whichever way you look at it."

Cunliffe said that "every day we find out more about the prime minister's office and dirty dealings and in this case the fact that his deputy chief of staff was involved with the SIS in dumping papers on Phil Goff, it's not right and that's why we need a very very broad inquiry around ministerial abuses of power."

It was a "sacking offence" if the deputy chief of staff had not briefed Key, he said.

The Inspector-General of Security and Intelligence launched an inquiry in response to the allegations that SIS documents were declassified so Slater's information request could be fast-tracked.

Goff gave evidence to the inquiry on September 8, and said the obvious explanation for the specificity of Slater's request was that he had a source for the information which "in the nature of SIS briefings could only have been either within the SIS itself or the prime minister or his office."