"We have asked the Prime Minister to apologise for the offence his comments have caused survivors of sexual violence and withdraw the statement," Poto Williams said.
During a debate about detainees on Christmas Island, Mr Key accused Labour and Green MPs of "backing rapists" at the offshore detention centre.
When he refused to apologise the following day, women MPs staged a walk-out from the debating chamber. Some women MPs who interjected were kicked out of the House. The incident was covered in news media around the world.
Speaker David Carter ruled that Mr Key's comments were unparliamentary, but did not make the Prime Minister withdraw them because no MP had complained at the time.