Prime Minister John Key says leaked Foreign Affairs documents did not come from the Beehive.
The Labour Party says an inquiry into who leaked confidential papers about the restructuring of the Ministry of Foreign Affairs and Trade (MFAT) may have uncovered a breach of Cabinet rules by a minister.
Foreign affairs spokesperson Phil Goff says inquiry head Paula Rebstock is now following information she apparently has that Trade Minster Tim Groser spoke out against the proposals to other senior public servants.
Mr Goff says on the face of it, that represents a fundamental breach of collective Cabinet responsibility and confidentiality.
Mr Key dismissed the allegations on Thursday.
"It's not at all unusual for a minister to be spoken to when these reports are done. Otherwise, they wouldn't be done with integrity and, in that regard, of course Tim would be a person that would be spoken to."
Mr Goff says the inquiry has backfired on the Government and while Mr Groser is facing scrutiny, the real culprit is Foreign Affairs Minister Murray McCully.
Mr McCully says it wouldn't surprise him if another minister was critical of the initial restructure proposal and defended Tim Groser.
"I don't think you can convict anyone for disagreeing with some of the content of the MFAT change proposals. I myself have expressed four pages of strongly expressed differences from those views."