Ardern said she understood that any decision to take further action would require the unanimous support of the committee and that had not occurred.
That was incorrect. A select committee needs a majority vote, not a unanimous vote.
Asked what she thought of Griffin's view that Curran's call was inappropriate, she said:
"I've even expressed that I thought under the circumstances it would have been better for someone else to have made that call".
Curran said it was not appropriate for her to comment given the select committee had yet to report to Parliament but Opposition leader Simon Bridges said Griffin should hand over the recording.
"This is about ultimately a minister's and the state broadcaster's accountability to Parliament. We've got so many unanswered questions here about what's gone on. It would be right to get to the bottom of that."
In his letter to the committee, Griffin outlined his reasons for declining the request to hand over the voicemail.
"The Minister's inappropriate call to me and the content of the message on the phone, whatever she said or meant, is not any part of the matter requiring correction."
He was asked for the voicemail when he and Thompson appeared last week to correct the record over comments he they made previously about the nature of a meeting between RNZ's former head of content Carol Hirschfeld and Curran.
The voicemail is central to determining whose account, Curran's or Griffin's, is correct about advice she gave him.
The recording either reveals Curran tried to persuade Griffin not to appear, as he has suggested, or that she was passing on advice that he need not appear in person if he was not able and a letter would suffice.
Hirschfeld was forced to resign after repeatedly lying to her bosses over a meeting she had with Curran in December. She had said it was a chance encounter but Curran later said it had been diarised.