Senior members of the National Party have failed to identify the person who secretly recorded them during a cocktail party.
Since the weekend, staff have been going through security camera footage from the Wellington Town Hall where National held its annual conference.
National leader John Key accused the Labour Party of infiltrating the conference, after the release of the secret recordings.
The security footage has now been viewed by deputy leader Bill English, Nick Smith and Lockwood Smith, the three MPs whose comments were recorded.
Mr Key says he has also "glanced" at the tapes but says he will not dedicate any more of his time to the footage, which he describes as low definition.
He says the party will continue to work its way through any other material that may surface.
Mr Key says "fair-minded New Zealanders" will see the recordings as a dirty trick.
Labour has rejected claims it is behind the tapes, calling the allegation a diversion tactic.
In one recording, Lockwood Smith said he hoped the party would be able to do things in government that are not current policy.
Mr English apologised after being recorded talking about eventually selling KiwiBank, saying that it was "loose language". The party leadership said it had no intention of selling the bank.
