As King Charles and Queen Camila prepares to kick off a nine-day visit to Australia, every single state premier invited to attend their royal reception Canberra on October 21 have all turned down the invitation on excuses as “schedule clashes” and “election campaign duties”.

In what is being described as a royal snub in the UK, the visit will be the King’s most significant overseas tour since his cancer diagnosis and his first to Australia as the nation’s head of state.

The King is due to address community and political leaders at the event, according to Buckingham Palace.

Victoria’s state premier Jacinta Allan was the latest leader to confirm she will not be attending, while South Australian premier Peter Malinauskas blamed a regional cabinet meeting for his expected absence.

Other premiers blamed workload from preventing them attending the reception, while Queensland’s Steven Miles said he will be concentrating on his election campaign.

Doctors have already given the 75-year-old permission to briefly halt his weekly treatment cycle in order to fly to Australia before a state visit to Samoa in the South Pacific.

The entourage will include the King’s doctor, while the programme of engagements has been designed to provide extra time for rest and recovery.