Anthony Albanese has been sworn in as Australia's new leader and will fly immediately to an international summit.
Mr Albanese's Labor Party defeated Scott Morrison's conservative government in an election on Saturday.
It remains unclear whether Mr Albanese will form a majority or govern with the support of crossbenchers.
The prime minister left for Tokyo on Monday to meet the leaders of the so-called Quad nations - the US, India and Japan.
Earlier in the day, he was sworn in with four key cabinet members, including new Foreign Minister Penny Wong, who is travelling with him to Japan.
Richard Marles is the new deputy prime minister and employment minister, Jim Chalmers is treasurer, and Katy Gallagher is attorney-general and finance minister.
It is Australia's first Labor government in almost a decade. The party has won 74 lower house seats but counting continues to determine whether they can get the 76 needed to form a majority.