Dr Smith was secretly recorded at National's weekend conference saying he hoped the party would be able to do some things that might not be policy at present.
Leaving a select committee on Wednesday surrounded by fellow MPs, Dr Smith refused to specify the policies he referred to during the recording. He would say only that he supports current party policy.
On Tuesday, National deputy leader Bill English apologised after he was recorded talking about selling KiwiBank.
National Party leader John Key has accused the Labour Party of being behind the secret recordings of the two MPs, saying Prime Minister Helen Clark needs to publicly disown the incidents of secret taping which he says were made by Labour Party activists.
Mr Key says National is considering going to police about the matter.
He says National wants to review security camera footage of the conference, and is taking legal advice on whether to approach police about the tapings.
Mr Key says the recordings were not made by genuine delegates, and that it has become clear Labour's tactics include bugging conferences and personal conversations, rorting the electoral law and condoning the stealing of emails.
But Miss Clark says she does not know the source of secret tapes of the MPs, adding that the real issue is why National says one thing in public and another behind closed doors.
Miss Clark says Mr Key's paranoia is getting the better of him.
Labour deputy leader Michael Cullen says the recordings raise questions about what National's real agenda is and whether it has plans to sell state assets.