The King has apologised after the decision was taken to postpone his forthcoming public duties after his cancer diagnosis.
In the statement, Buckingham Palace said Charles would continue to “undertake State business and official paperwork as usual” and he will continue having weekly audiences with the Prime Minister.
The recent diagnosis means the King is unlikely to be at the Commonwealth Day service at Westminster Abbey on March 11, which is usually attended by senior members of the royal family.
The King and Queen were expected to visit Canada in May, and Australia, New Zealand and Samoa for the Commonwealth Heads of Government Meeting (CHOGM) in October.
Buckingham Palace has yet to confirm whether the tours will go ahead, with no date suggested for the King’s return to full public duties.
His cancer diagnosis raises the prospect of the high-profile overseas visits – his first to the countries as King – being postponed.
No forthcoming state visits have officially been confirmed by the Palace.
The palace said the King “looks forward to returning to full public duty as soon as possible”, but it is not yet known whether it will affect his attendance at events such as those marking the 80th anniversary of D-Day in June.
It is understood he will continue to receive red boxes and process state documents during treatment and there are no plans to appoint Counsellors of State.
A palace spokesman said: “Regrettably, a number of the King’s forthcoming public engagements will have to be rearranged or postponed.
“His Majesty would like to apologise to all those who may be disappointed or inconvenienced as a consequence.”
It is understood details of the King’s diary are still being worked on and it is not yet known when a full programme of engagements will begin.
The palace said the Queen will continue with a full programme of public duties.
Other working members of the royal family could undertake additional duties on behalf of the King but it is understood planning for future state visits will continue where possible.
The Prince of Wales could take on some of the King’s work as he is expected to return to public duties on Wednesday after the Princess of Wales’ major abdominal surgery last month.
It is also understood that Charles will continue to be available for Privy Council meetings, but details of how they will take place are still being worked through.
It is expected that alternative arrangements will be made for his weekly audience with the Prime Minister should doctors advise him to minimise any in-person contact.