Prime Minister-elect Tony Abbott will attend the Commonwealth Heads of Government Meeting in Sri Lanka.
Mr Abbott confirmed his attendance at the November summit in a telephone call with Sri Lankan president Mahinda Rajapaksa on Wednesday.
The Colombo event will be the first CHOGM not attended by Queen Elizabeth II in 40 years.
Prince Charles will be attending in her absence.
It will also be a politically controversial event.
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Canada has threatened to boycott it to protest Sri Lanka's human rights record.
The British House of Commons foreign affairs committee called on British PM David Cameron not to go, on similar grounds, but he has confirmed his attendance.
Perth hosted the most recent CHOGM in 2011.
A delegation of Australian officials who were involved in the 2011 summit visited Sri Lanka in June to help with planning the 2013 event.
