National Party MP Nick Smith says a spate of secret recordings are damaging for democracy.
Dr Smith was secretly recorded at a cocktail party last weekend talking about National's election strategy.
It is the third recording of a senior National MP to surface from the event. Other recordings were of Bill English discussing KiwiBank and Lockwood Smith saying the party wants to do things which are not policy right now.
National blames Labour for "dirty tricks". Labour wants an apology.
Dr Smith told Morning Report the person who approached him said he was a member of the Young Nationals and asked him for his views on KiwiBank, Working for Families and nuclear energy.
He says he doesn't know who the man was but would know him if he saw him again.
Dr Smith says there will have to be increased security at party conferences in future and MPs will be less frank about their views with young people.
National has requested security footage of the event.
It says that rubbish at party leader John Key's Helensville electorate office appears to have been ransacked for the second time in a month.
Diversion tactic- Cullen
Deputy Prime Minister Michael Cullen says National has no real basis for what he calls its "wild claim", which he describes as a diversion tactic.
Dr Cullen says photographs distributed by National of Mr Key's rubbish look like a dog has gone through it looking for leftovers.
A National spokesperson says it's clear Labour is behind the tapes because they've been recorded by National's opponents.
Mr Key said on Wednesday the recordings were not made by genuine delegates. He told Morning Report it has become clear Labour's tactics include bugging conferences and personal conversations, rorting the electoral law and condoning the stealing of emails.
Prime Minister Helen Clark says Mr Key's paranoia is getting the better of him.