Allegations are flying today over the release of Security Intelligence Service documents to Whaleoil blogger Cameron Slater.
The Prime Minister says he wasn't made aware of the 2011 Official Information Request by the blogger, but Phil Goff claims he is "not telling the truth".
Here is a timeline of what has emerged so far:
August 14, 2014:
Nicky Hager's book Dirty Politics alleges that John Key's office had a hand in ensuring Mr Slater received confidential information under the Official Information Act.
The documents related to a meeting Mr Goff had with the SIS in 2011 when he was leader of the Labour Party.
The meeting became an issue in 2011 when questions were raised about whether Mr Goff was briefed by the then SIS director about an Israeli spy investigation.
Mr Goff had denied he was briefed about it, but then Warren Tucker, who was the director of the SIS at the time, released information to Mr Slater which suggested otherwise.
Mr Slater posted the heavily blackened document on his blog. The document showed the investigation was listed as an issue to be discussed during the meeting, and the page the SIS titled "Investigation into Israeli Nationals in Christchurch" had a diary note on the top corner "read by/discussed with Mr Goff 14 Mar 11".
Mr Goff continued to deny he was briefed on the investigation after the blog post.
Mr Goff said he was surprised by the release as he had been sworn to secrecy about the meeting, saying he was told he couldn't tell anyone about the nature of the meeting, he couldn't have anyone else with him for the briefing, and couldn't take notes or keep documents.
The SIS released the information quickly after receiving Mr Slater's request under the Official Information Act. This raised questions as most requests take several weeks to action if they are not rejected outright.
Mr Hager's book claims Mr Slater was tipped off to ask the spy agency for the specific documents about the 2011 briefing in a bid to discredit Mr Goff.
August 20, 2014:
The Inspector-General of Intelligence and Security Cheryl Gwyn announces she will investigate the allegations made in Mr Hager's book and will examine the declassification and release of the documents.
Mr Key says he welcomes the investigation and is adamant his office had nothing to do with the speedy release of the documents to Mr Slater.
"I just know I wasn't told.
"What happens is my office gets told an OIA (Official Information Act request) is going out but more often than not they don't tell me," said Mr Key.
Mr Goff says the inquiry should address whether the Whaleoil blogger was tipped off by National to request the specific document and why preference was given to him ahead of similar requests from other media.
August 21, 2014:
Mr Goff presented a letter from the SIS signed by Mr Tucker on TV ONE's Breakfast programme this morning.
The letter was sent on November 9, 2011, to Newstalk ZB in response to an Official Information Act request.
"And about the information given to the Prime Minister he says, look, 'I notified the Prime Minister. I advised the Prime Minister. I informed the Prime Minister'.
"That shows that Mr Key was not telling the truth when he said he was not told. Warren Tucker contradicts what he said absolutely," Mr Goff told Breakfast.
At Auckland Airport this morning, Mr Key said he was not told personally about the OIA request from Mr Slater about the SIS briefing.
The Prime Minister said his office was informed and the term "advising the Prime Minister" is a generic term.
"If I was told about every OIA request that came through my office I wouldn't have time to run the country," Mr Key told ONE News.
Dr Tucker released a statement this morning backing up Mr Key's comment, saying his reference to the Prime Minister in his letter "in this context means the PM's office".
Ombudsman Beverley Wakem says Dr Tucker and Mr Key are correct.
Mr Goff told Breakfast: "Just consider it for a moment, Cameron Slater knew what was in the document being released, he knew that it was being expedited, and he said the he was sworn to secrecy, he knew all of that before he received the document.
"Either the SIS told him or John Key. Who do you think had the vested interest in telling Cameron Slater what was in the document?"
Green Party co-leader Metiria Turei says the Inspector General's decision to investigate "puts John Key's defences really lying in tatters on the floor".
August 21, 2014:
Footage of a Cabinet press conference on August 8, 2011 has re-surfaced today, in which Mr Key appears to suggest that former SIS director Warren Tucker had informed him about Mr Slater's Official Information Act request.
In the 2011 footage, Mr Key says that when Mr Tucker found out about Mr Slater's request for classified information, he contacted the SIS' legal advisors.
"His legal advisers told him this is the process they have to follow and when he was going through that process it was at that point he told me he'd released them because he has to tell me that under the no-surprises doctrine," Mr Key says on the recording.
A spokeswoman for Mr Key said this morning that the Prime Minister still stands by his statement yesterday "that his office knew about the OIA prior to its release, but he didn't."