China's efforts have included extraordinary quarantines in Wuhan and surrounding cities, with all transport out banned, effectively sealing off more than 50 million people.
But 10 days after locking down Wuhan, authorities imposed similar draconian measures on Wenzhou, a coastal city of nine million people in Zhejiang province, part of the eastern industrial heartland that has powered China's economic rise over recent decades.
Only one resident per household is allowed to go out every two days to buy necessities, and 46 highway toll stations have been closed, authorities announced.
The city had previously closed public places such as cinemas and museums, and suspended public transport.
Zhejiang has more than 660 confirmed infections, with several hundred of those in Wenzhou, according to the government.
This is the highest tally for any province in China after ground-zero Hubei.
The United States, Australia, New Zealand and Israel have banned foreign nationals from visiting if they have been in China recently, and they have also warned their own citizens against travelling there.
Mongolia, Russia and Nepal have closed their land borders.
The number of countries reporting infections rose to 24 after Britain, Russia and Sweden confirmed their first cases this weekend.
There were 2,829 new confirmed cases nationally on Monday, bringing the total infected to 17,205, health officials said.
With hospitals in Wuhan overwhelmed, China will open a military-led field hospital Monday that was built in just 10 days to treat people stricken by the virus.
And with the Chinese economy suffering, the central bank announced it would release 1.2 trillion yuan ($173 billion) on Monday to maintain liquidity in the banking system -- the day markets re-open after the long holiday break.
The emergence of the virus coincided with the Lunar New Year, when hundreds of millions travel across the country in planes, trains and buses for family reunions.
The holiday, which was scheduled to end on Friday, was extended by three days to give authorities more time to deal with the crisis.
With many due back at work on Monday, people were starting to return on planes and trains over the weekend, with almost everyone wearing face masks.
Customs authorities had ordered temperature checks at all exit-entry points in Beijing, according to state media.
Returning travellers were being checked and registered at residential compounds, while fever checks were in place in subway stations, offices and cafes.
One 22-year-old arriving at a Beijing train station from northeastern China said her family had urged her to delay her return.
"But I was worried it would affect my job," she said.
Security guard Du Guiliang, 47, said he would be starting back at work in Beijing on Sunday, after returning from northeast Liaoning province.
"Many colleagues (from Hubei) couldn't come back. Now, those who work the day shift at our company have to do the night shift as well," he said.
Many businesses were to remain closed for at least another week, however, while some major cities -- including Shanghai -- had also extended the holiday. (AFP)