The cancer diagnosis for 75-year-old King Charles III was made early, UK Prime Minister Rishi Sunak said on Tuesday.

"Thankfully, this has been caught early and now everyone will be wishing that he gets the treatment that he needs and makes a full recovery," Sunak told the BBC.

The British leader said he is in regular contact with the monarch after his cancer diagnosis and that their communication would continue as normal.

"I think that's what we're all hoping and praying for and I am, of course, in regular contact with him and will continue to communicate with him as normal." 

Buckingham Palace said on Monday that Charles had been diagnosed with cancer and had begun treatment, sparking a flood of support from around the world. 

Charles, who became king upon the death of his mother, Queen Elizabeth II, on September 8, 2022, has generally enjoyed good health, barring injuries from polo and skiing. 

But the palace said that during his recent hospital procedure for benign prostate enlargement, "a separate issue of concern was noted".

"Many families around the country who are listening to this will have been touched by the same thing and they know what it means for everyone," Sunak said. 

"So we'll just be willing him on and hopefully we'll get through this as quickly as possible."