The Prime Minister has told Parliament he has no knowledge of his communications manager having any input into a show on Radio Live that has since been referred to police.
John Key was the on-air host for an hour-long show, two months before the general election in November.
The Electoral Commission found the programme breached the Broadcasting Act and has referred the matter to police.
Mr Key says Radio Live was responsible for the editorial content, so it is the broadcaster's problem, not his.
Labour's deputy leader Grant Robertson asked Mr Key whether his office had any control over the content of the show.
He then tabled an email "from the communications manager of the Prime Minister's office where it states that he has made some tweaks to the brief and gives the details of an email that was subsequently sent in Radio Live's name".
Mr Key said he had no knowledge of the email, or the involvement of the staffer.