Prime Minister John Key has confirmed that the Ministry of Foreign Affairs and Trade is investigating the leak of a diplomatic cable from its Canberra high commission.
The Australian newspaper has published extracts from a briefing prepared by the New Zealand High Commission in Canberra, which contains details of some of the deal making leading up to Kevin Rudd's resignation as Australia's prime minister.
Mr Key says the Government has no comment on Australian politics, and diplomatic cables are produced for internal consumption only.
He says officials are looking into the possible leak, and will try to piece things together as best they can.
Mr Key says he did not personally see the cable in question.
The Australian newspaper says it is likely to publish more stories from the leaked diplomatic cable.
The paper's political editor, Dennis Shanahan, says he has established the document's authenticity, and independently verified some of its contents.
Rudd for UN role - reports
Newspapers in Australia are reporting that Mr Rudd is being considered for a top job as a climate change adviser at the United Nations.
The Labor Party is denying the reports, saying that Mr Rudd is committed to standing again for Parliament for the seat of Griffith in next month's elections.
News Ltd papers quote an unnamed source who says Mr Rudd could be made a special envoy or an ambassador reporting directly to the UN secretary-general.
They say the UN "refused to hose down speculation" on the appointment.
The ABC reports Mr Rudd was in New York last week and met UN Secretary-General Ban Ki-moon.