Britain will tell 1.5 million of its most vulnerable citizens they must stay at home for the next 12 weeks to protect themselves from the coronavirus, a minister said on Sunday.

"Today, we have to go further and shield the most clinically vulnerable people to save their lives," communities minister Robert Jenrick said at a news conference with Prime Minister Boris Johnson.

"The [National Health Service] will be contacting these people in the coming days urging them to stay at home for a period of at least 12 weeks."