King Charles and Queen Camilla will carry out TEN engagements a day on newly-announced Australia tour despite his ongoing cancer treatment - while the royals are changing traditional phrasing for trips to avoid potentially causing offence

The King and Queen will undertake up to ten engagements a day on their official trip to Australia and Samoa next month – despite his continuing cancer treatment.

While aides say they have calibrated his diary to 'protect and prioritise' his health and recovery, including fewer evening engagements and a 'rest day' on his arrival in Sydney, King Charles clearly isn't planning to take it easy.

Buckingham Palace officials would not be drawn on whether His Majesty would still be undergoing weekly treatment – as he is now – by the time he arrives in Australia on October 18. They would only confirm the 'trajectory' of his current treatment was going 'very well'.

But he and his wife, Queen Camilla, aged 75 and 77 respectively, are still going to set a cracking pace after a gruelling year for the monarch, diagnosed with an undisclosed form of cancer in January.

The King has continued to work throughout his treatment, but the nine-day trip – more than 30,000 miles door to door – will be his biggest challenge so far.

A royal official said 'we have had to be thoughtful about how to balance' the King's diary and 'particular thought' had been given to what and how many engagements he would undertake.

They also admitted that some 'tough decisions' had been made on what visits should take priority, with a planned stop in New Zealand having reluctantly been cancelled in full on his doctors' advice.

In a sign of sensitivities, the familiar royal term 'walkabout' - described when members of the family meet and greet waiting members of the public - will not be used on the tour out of respect for Australia's indigenous communities.

The phrase, which has been in use for decades by Buckingham Palace, will be replaced with 'opportunities to meet the public' in any official descriptions for this particular trip.

In Aboriginal culture 'walkabout' means when a person travels on foot into the bush in times of change, grief or coming of age.

It is the first time that such a change has been made despite members of the royal family visiting the country hundreds of times.

It will be the King's 17th visit to the country alone.

The visit to Australia, Charles' first to a realm of which he is head of state since he became King two years ago, will take in both Sydney and the capital Canberra.

He will then travel to Samoa in the South Pacific for his first state visit to the country, where he will attend the Commonwealth Heads of Government Meeting as its titular head. He previously visited Samoa unofficially as a young man while in the Royal Navy.

A Palace spokesman said: 'We've had to, as you would with any visit, think about how you can ensure Their Majesties' energies are preserved to be at their best.

'There had been some hope earlier in the year for Their Majesties to be able to visit New Zealand. On doctor's advice, and in close consultation with the Australian and New Zealand governments, that wasn't able to take place.'

The couple will meet Australian prime minister Anthony Albanese, a life-long republican, undertake cultural and military engagements and meet celebrated Australians, including Aboriginal leaders.

Significantly, and no doubt emotionally, the King will meet two of the country's most eminent melanoma experts, Professors Georgina Long and Richard Scolyer, to hear of their research into one of Australia's most common cancers. Professor Scolyer is himself battling a form of brain cancer.

They will also lay a wreath at the Australian War Memorial and visit the Aboriginal and Torres Strait Islander memorial, 'For Our Country'. The King will learn more about Australia's work to combat bush fires caused by climate change, while the Queen will undertake solo engagements to highlight domestic violence and literacy. There will also be a community BBQ in Sydney.

In Samoa, they will be greeted with an Ava Fa'atupu ceremony – a ritual in which a drink is shared from a traditional dish – before meeting Samoans at an engagement to highlight aspects of their traditions and culture.

Finally, he will take part in the Commonwealth Heads of Government Meeting with delegations representing the 56-strong 'family of nations'.

The tour's cost will be jointly met by the Australian and British governments, on whose request it is taking place.