Jane Patterson, Political Editor
Power Play - A major pre-Budget bomb has dropped on the Beehive with top level Budget information ending up in the hands of the National Party.
National Party leader Simon Bridges. Photo: RNZ / Dom Thomas
The Prime Minister's regular media stand-up at Parliament this morning was ticking along with questions about mental health, funding for dentistry and the Debbie Francis report when the news broke - the timing was of course no coincidence.
Jacinda Ardern was blindsided and reporters had just enough time to digest the document released by National before heading to leader Simon Bridges' regular Tuesday question and answer session.
"National reveals Budget details" screamed the headline on the media release.
With it was a document claiming to reveal the funding for 18 policy areas for the next financial year.
It spanned major portfolios including health, defence, overseas aid, customs, Maori development and justice.
"This is not the Wellbeing Budget it's the Winston Budget", declared Mr Bridges.
That's a reference to Deputy Prime Minister and New Zealand First leader Winston and a $1.3 billion spend on defence assets in National's documents.
But Mr Bridges was a lot more reticent when asked about how National had come across the information - "cock-up or conspiracy?" asked one reporter.
One possibility is that someone within the Government deliberately leaked the material to National.
Mr Bridges talked about a "loose and incompetent" government and would not go as far as calling it a leak, so that seems less likely.
More likely is that someone has been careless with the information and it has ended up with National through human error.
Budget information is always very closely guarded and treated as highly sensitive.
For any of it to end up in the hands of the Opposition is a serious breach.
The Finance Minister Grant Robertson hastily convened a media conference where he said some of the figures were right, but some were wrong.
The "major new initiatives", he said, were not in the National Party document.
The only specific comment he made was about the defence spending, confirming it does includes the purchase of Boeing P-8A Poseidon Aircraft, which had already been announced.
But other than that he refused to say which other parts were right or wrong, or even how much of it was accurate.
The hunt for who was responsible will only begin in earnest once the Budget has been delivered on Thursday, but Treasury is already investigating.
One notable feature of the information held by National is that it's just for the next financial year, while the Budget is always presented as a four-year funding stream.
Mr Robertson was "confident" the leak had not come from the Beehive.
RNZ understands four agencies or companies held the information in the way it was presented: Treasury, the Parliamentary Counsel Office (that drafts Budget related legislation), the Office of the Auditor General and Printlink.
There are various theories floating around, including a website glitch from a key agency. But for now the most senior ranks of the government are now trying to ensure the attention remains on Thursday's Budget, not on an embarrassing mistake - wherever it's occurred.