King Charles 'frustrated' by pace of cancer recovery

Britain's King Charles is "frustrated" by the pace of his recuperation from cancer, his nephew Peter Phillips said on Sunday, becoming the first member of the royal family to speak in detail about how the monarch was faring.

The insight into the king's mindset comes after Kate, Britain's Princess of Wales, said on Friday she was undergoing preventative chemotherapy after cancer was found to be present, a fresh health blow to the royal family.

Phillips, the eldest of the late Queen Elizabeth's eight grandchildren and son of Princess Anne, told Sky News Australia in an interview that the King was frustrated as his recovery was taking longer than he'd like.

"He's frustrated that he can't get on and do everything that he wants to be able to do," he said, adding that while he was pragmatic and understood the need for recovery time, he was eager to get back to normality.

Britain's Queen Camilla said her husband Charles was doing "very well", as she greeted crowds on a visit to Northern Ireland on Thursday.