China sealed off millions more people near the epicentre of a virus outbreak on Friday, shutting down public transport in an eighth city in an unprecedented quarantine effort as the death toll from the disease climbed to 25.

While the World Heath Organization held off on declaring a global emergency, despite confirmed cases in half a dozen other counties, China expanded a lockdown now covering some 26 million people and cancelled some Lunar New Year celebrations to prevent the disease spreading further.

Besides the provincial capital Wuhan, seven other smaller cities nearby have taken measures to batten down the hatches.

In the latest, the city of Huangshi, which has a population of more than two million, announced on Friday that it had halted public transport and closed a major bridge.

On Thursday, Huanggang, a city of 7.5 million people, announced that public transport and train services were suspended and citizens were told to not leave the city.

Meanwhile, the straitjacket on Wuhan tightened further Friday, with the city limiting the number of taxis allowed on roads from noon, and hugely popular Chinese ride-hailing service Didi Chuxing saying it was temporarily suspending services there.

With hundreds millions of people travelling across the country this week for the Lunar New Year holiday, the government has halted all travel out of the city, municipal public transport has been suspended, and residents have been ordered not to leave home.

Very few flights were coming into Wuhan, too, further isolating the city from the rest of the world.

The measures have rendered the city of 11 million an eerie ghost town, with streets and shopping centres deserted, and stores shuttered at a time normally marked by festive gatherings and shoppers out enjoying China’s most important festival.

“This year we have a very scary Chinese New Year. People are not going outside because of the virus,” a taxi driver in the city, who asked not to be named, told AFP.

To discourage nationwide holiday travel, the government said beginning on Friday, anyone who bought a ticket for rail, air, long-distance coach, or water transport could receive a refund upon cancellation.

The virus that emerged in Wuhan took eight more lives, the government said in its latest update, as the number of confirmed cases also leapt to 830. (AFP)