The number of days King Charles III and Queen Camilla’s stay in Samoa would be subject to the health of the British monarch says a statement from Buckingham Palace.

The statement had now confirmed that the King and Queen are set to visit Australia and Samoa in October, as the King takes on more public duties while receiving cancer treatment.

The pair will have engagements in the Australian Capital Territory and New South Wales, before heading to Samoa for a Commonwealth summit.

The King will make the lengthy journey despite his diagnosis of an undisclosed form of cancer earlier this year.

But Buckingham Palace has confirmed that the couple will not visit New Zealand, saying doctors have advised against an extended visit on health grounds.

"In close consultation with the Australian and New Zealand prime ministers, and with due regard for the pressures of time and logistics, it has therefore been agreed to limit the visit to Samoa and Australia only," the Palace said in a statement.

There were media reports about this before, but all speculations have been laid to rest with the official statement issued two days ago.

This will be the King's first visit to Australia as Monarch. It is also his first official overseas tour since his cancer diagnosis.

In Samoa, they will attend the Commonwealth Heads of Government Meeting which starts on 21 October and finishes on 25 October

The couple are expected to attend the Commonwealth Heads of Government Meeting (CHOGM), which brings together delegations from the 56 countries in the Commonwealth.

Further details of the visit to the two countries are expected to be announced shortly, and the couple's programme and schedule changes will be subject to doctor's advice.

The 75-year-old monarch last visited Australia in 2018 with the Queen for the Gold Coast Commonwealth Games.

Australians narrowly voted against cutting ties with the monarchy in a referendum in 1999, but calls have continued in the quarter-century since for another ballot.

It is a longstanding policy of Australia's Prime Minister Anthony Albanese to hold a vote on becoming a republic - but in January the government indicated that it has put that referendum on hold, saying it was not a priority.

Buckingham Palace confirmed in February that the King would pause some public events while receiving treatment for cancer.

At the time they said it was not prostate cancer, and that it was discovered during treatment for an enlarged prostate.

The King later returned to public-facing engagements in April when he spoke to patients at the University College London Hospital about the "shock" of hearing about his cancer diagnosis.

In recent weeks, he visited Normandy as part of a D-Day commemoration event, hosted actor Idris Elba for a summit on tackling youth crime and hosted the Japanese emperor and empress during their state visit to the UK.