At the urging of the ASB Great Debate's moderator, Patrick Gower, Finance Minister Steven Joyce said he could categorically deny the leak had come from the Beehive.
The New Zealand First leader said the National Party ''broke the law and they're not going to get away with it'', ignoring a call from Act Party leader David Seymour to make all his correspondence about the matter public.
The evening was marked by frequent verbal jousting between Messrs Peters and Seymour, which began when Mr Peters told the latter he was behind in the polls in Epsom: ''This is your valedictory speech.''
Their frequent testy exchanges prompted Mr Joyce to liken the pair to a ''couple of chihuahuas''.
Tax was a recurring theme, with Mr Gower asking the participants for their parties' stances on three of the new taxes being promised by opposition parties.
On the question of a capital gains tax, Mr Peters refused to say if he would stop Labour from introducing one during post-election negotiations.
Instead he urged Labour finance spokesman Grant Robertson to tell the public what the tax rate would be before the election rather than waiting for a report from an expert working group.
On an international tourist tax, of which the Labour and Green parties have different versions, Green Party leader James Shaw said he was confident such a border levy would have no significant impact on tourist numbers.
Mr Peters said the Government should instead return a much larger portion of GST receipts from tourism back to the regions where it was generated, such as Queenstown.
