UK Health Secretary Matt Hancock announced the detection of another new strain of coronavirus believed to have originated from South Africa.

Hancock said all travelers that arrived into the country from South Africa over the past two weeks and their close contacts must isolate immediately.

Britain's transport minister later said he had ordered flights and arrivals from South Africa to be halted.

"I've taken the decision to temporarily stop flights and arrivals entering England from South Africa from 9 a.m. tomorrow following an outbreak of a new strain of coronavirus," Transport Secretary Grant Shapps tweeted.

"British & Irish Nationals, visa holders and permanent residents arriving from South Africa will be able to enter but are required to self-isolate for ten days along with their household," Shapps said. "Visitors from South Africa will not be permitted to enter, to stop the spread of COVID-19."

This second variant of the virus – called 501.V2 – is the second mutated strain to be announced by the UK Government in as many weeks.

Hancock said the new version is even "more transmissible" and has "mutated further" than the one which emerged in Kent.

The health minister also announced a raft of new restrictions which will see more regions of the country join London in tier four starting midnight Boxing Day on December 26.

(With input from agencies)