British Prime Minister Boris Johnson has announced stricter new curbs on movement in the United Kingdom to halt the spread of novel coronavirus, urging people to simply stay at home.

From Monday night, people are only allowed to leave their homes for very limited purposes.

"Shopping for basic necessities, as infrequently as possible. One form of exercise a day — for example a run, walk, or cycle -- alone or with members of your household. Any medical need, to provide care or to help a vulnerable person," Johnson said.

But he restricted travel only to and from essential work, such as NHS, where this cannot be done from home.

Johnson said police will have the power to enforce the rules when people are not complying with them.

Parks will remain open for exercise but gatherings will be dispersed. All public assemblies of more than two people, excluding people who live together, will be banned, the prime minister said.