Prime Minister John Key says he heard a rumour about National MP Richard Worth's conduct toward women some years ago.
Dr Worth resigned from his ministerial post after a woman laid a police complaint against him of a "sexual nature".
Labour Party leader Phil Goff has made public a separate allegation of sexual harrassment by a different woman against Dr Worth.
Dr Worth has denied the allegations.
Mr Goff says that when he called Mr Key to tell him about the complaint, Mr Key replied that he had heard rumours of similar behaviour, which was why Dr Worth was not made the Speaker of the House.
But Mr Key says that is not true, and that National always intended to make Lockwood Smith the Speaker.
He says he only ever heard one rumour, and when he challenged Dr Worth on it some years earlier he denied it.
Mr Key would not disclose what the rumour was.
