Prime Minister Bill English says he does not know whether the recording at the centre of the Todd Barclay controversy still exists.
Mr English revealed at the weekend Mr Barclay, the Clutha-Southland MP, offered to play him the recording of an electorate staff member but he turned it down.
Mr English told Morning Report's Susie Ferguson he did not know if any recordings still existed or whether any had been destroyed, and he gave no advice to Todd Barclay about the matter.
"There's a whole lot of the detail of this I simply don't know," he said.
"It's all been covered by a 10-month police investigation.
"I didn't set out to investigate the issues because that was being covered by the police.
"I knew one thing about it, which was the conversation I had with Todd Barclay. I passed on the contents of that conversation to the relevant people."
The Todd Barclay story refused to die at the National Party's election year conference over the weekend, despite the best efforts of senior government ministers.
The Party's president, Peter Goodfellow, backed his Board and said they acted with integrity and professionalism throughout the Todd Barclay affair.
At the conference our political editor, Jane Patterson, asked Mr Goodfellow what contact there had been between board members and party members in Clutha Southland, including Ms Dickson.