Photo taken on December 14, shows Christmas decorations on a street in Rome, Italy. (Photo: Xinhua)

Millions of people in England and Italy will celebrate Christmas under tough new coronavirus restrictions as Europe battles a winter surge including a more infectious new strain.

Europe has become the first region in the world to pass 500,000 deaths from COVID-19 since the pandemic broke out a year ago, killing more than 1.6 million worldwide and pitching the global economy into turmoil.

In England, where a lockdown-weary population had been looking forward to a temporary five-day relaxation of virus restrictions over the festive period, British Prime Minister Boris Johnson instead announced a new "stay at home" order for London and southeast England - an area including around a third of the country's population. The move follows alarm at the speed at which the virus was spreading and a new strain that Johnson said was "up to 70 percent more transmissible."

"It is with a very heavy heart I must tell you we cannot continue with Christmas as planned," he told the nation in a televised briefing on Saturday.

"Alas when the facts change, you have to change your approach," he said.

Residents in the affected areas will have to go into lockdown at least until December 30, Johnson said, tearing up earlier plans that would have allowed up to three households to mix.

Hours later the Netherlands banned all passenger flights from Britain after finding the first case of the new, more infectious virus strain that is circulating in the UK. The ban is in effect from 0500 GMT Sunday until January 1, 2021.

The Netherlands is under a five-week lockdown until mid-January with schools and all nonessential shops closed to slow a surge in the virus.

Italy also announced a new regime of restrictions until January 6 that included limits on people leaving their homes more than once a day, closing nonessential shops, bars and restaurants and curbs on regional travel.

"It's right that they prohibit departures after 20 December if it means travelling in safety," Claudia Patrone, a 33-year-old lawyer, told AFP as she got off a train in Milan.

"I took the test before leaving, I stayed locked in my house, I didn't see anyone. The measure is right if everyone respects the rules and guarantees safety."

Europe - the epicenter of the pandemic earlier in 2020 - is once again seeing growing cases with officials fearing an explosion in infections after the Christmas holidays as families gather.

Europe is expected to start a massive vaccination campaign after Christmas following the US and Britain. Slovakian Prime Minister Igor Matovic became the latest high-profile figure to test positive for COVID-19 a week after attending a EU summit in Brussels. The summit is believed to be where French President Emmanuel Macron also caught the virus.