The police interview in which Bill English is questioned over his knowledge of a secret taping has been released to media.
Mr English was questioned by police after Clutha-Southland MP Todd Barclay was accused of secretly recording staff member Glenys Dickson.
Mr English found himself facing tricky questions after initially downplaying his knowledge of the scandal.
It then emerged the police had interviewed him about the matter.
The issue plagued Mr English leading up to the election campaign, and was brought to a head by NZ First leader Winston Peters, who accused him of sending more than 450 text messages to Ms Dickson in the 12 months before her resignation.
When questioned by media, Mr English said he had no record of the alleged 450 messages but didn't directly deny the messages had been exchanged.
In the audio of the police interview, Mr English told police he knew of the recordings because Mr Barclay had told him he had recordings of Ms Dickson criticising him.
"He said he just left the dictaphone on," Mr English told police in the recording, which was released to Fairfax under the Official Information Act.
Mr English told police he could not recall what prompted Mr Barclay to confess to recording Ms Dickson. Mr English also said he didn't know whether Mr Barclay was present when the recordings were made.
Police likely asked that question because in New Zealand it is illegal to record someone without being present.
Mr English had known Ms Dickson for 16 years. She had worked for Mr English when he'd been an MP for Clutha- Southland.
Police re-opened its investigation into the recordings in July, which was when Mr English released the full transcript of the interview.