Finance Minister Bill English sparked a debate by raising the prospect when answering questions in a post-budget speech last month.
Mr English said Kiwibank had reached a size where it needed either a government guarantee or "an awful lot of capital" and suggested there would be strong demand for shares in it.
Back in 2008 Mr English was covertly recorded saying that National will sell Kiwibank "eventually, but not now".
Ever since the Government has repeatedly said it has no intention of selling any SOEs and if the policy changed it would be campaigned on.
Today Kiwibank architect and Progressive leader Jim Anderton asked Mr Key if he would hold to promises he made before the election to never sell Kiwibank.
He cited an October 22, 2008, article where Mr Key, in answer to a reader's written question said: "I am ruling out selling Kiwibank at any point in the future."
Then on television during a November 3 leaders debate: "National would not sell Kiwibank at any stage, ever. We have ruled it out."
Mr Key said the Government policy was not to sell any state assets this term.
"What happens in future terms is something we will have to consider as we go into future elections."
Mr Anderton then asked: "Does he accept that this is a different position from his repeated pledges before the last election that he would never sell Kiwibank, ever?"
"No, I do not," was the response.
Earlier in the day State Owned Enterprises Minister Simon Power appeared before Parliament's finance and expenditure select committee and, under grilling by Mr Anderton and Labour's Clayton Cosgrove, said he had got no advice on either future sales or rationalisation of SOEs.
"An initial discussion is going to be required as to whether there's going to be any change in policy or whether it's worth having a further discussion about a change in policy. Remember there's nothing on or off the cards here. It may well be that there is no change to policy."
He declined to speculate about what model he would prefer if the Government did change its policy and said as far as he was concerned nothing had changed since his appearance before the committee last year.
Mr Cosgrove found it puzzling that one shareholding minister, Mr English, would hypothesise "very specifically, very loudly over the potential asset sale of Kiwibank, and in my view the primary shareholding minister which is you, has not formed a view, has not contributed to any discussions, has not thought about it, dreamed about it or discussed it with your counterpart. I mean that lacks a tad of credibility."
Mr Power retorted: "Believe me Mr Cosgrove what I dream about would be of no interest to this select committee... I don't speak for comments made by the Minister of Finance. All I am saying to you is as Minister of State Owned Enterprises... I have neither sought nor received any advice from Treasury on the issue."
Mr Power said there had been no formal Cabinet discussion about the issue and his conversation with Mr English was only to express interest in hearing his comments.
Mr Cosgrove said that was astounding.
Also today Mr Power released financial performance measures which SOEs will be expected to include in their Statements of Corporate Intent from 2010/11 as part of moves to improve the transparency and accountability of the SOEs.
