Tens of thousands of people have fled Wuhan, the original epicentre of COVID-19, following a strict 11-week lockdown of its 11 million residents.

As people rushed to resume work and lives in other parts of the country, about 55,000 people fled Wuhan by train alone, while 100 commercial flights took off for the first time since January 23 to cities such as Shanghai, Beijing, Shenzhen and Chengdu.

A photo showing packed crowds at a Wuhan train station has raised concerns of a resurgence of the virus.

Authorities are walking a fine line between allowing morefreedom of movement, while also guarding against a second wave of infection.

There is particular concern around imported cases and asymptomatic people who can still pass on the virus

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There were also massive queues of cars getting onto highways as roads reopened.

Wuhan was abruptly locked down on January 23, with no one able to leave the city, to contain the outbreak of COVID-19.

That left many residents from other parts of China stuck in the locked-down city, including about 11,000 people from Beijing.

The measures appeared to have been effective, according to Chinese authorities, who reported no new deaths or locally transmitted cases on Monday. Wuhan's coronavirus cases are believed to account for 61 per cent of all cases in China and about 80 per cent of the country's deaths, according to official figures.

Amid the mass exodus, celebrations rang out after midnight as people cheered for their long-awaited freedom. Skyscrapers lit up with lightshow animations paying tribute to the city's medical workers as residents danced and sang on the streets.

Meanwhile, supermarkets, shops and cafe are back in business today.

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Authorities are keen to get people back to work in Wuhan after the lockdown ravaged the city's economy.

But the lifting of lockdown does not mean life has totally returned to normal, as risks linger of a resurgence of the deadly virus.

In Wuhan, schools are still closed and people are still getting health checks before entering buildings, AP reported.

And while those leaving Wuhan can do so without special authorisation, a mandatory phone app is being used to track that they are healthy and haven't been exposed to a coronavirus case.

Beijing has ordered anyone entering the city from Wuhan will need two health checks and be quarantined for 14 days at an approved site. Other cities also require people from Wuhan to get tested.

But people are thrilled to be no longer cooped up indoors.

Wuhan resident Tong Zhengkun was one of millions of enjoying a renewed sense of freedom.

“Being indoors for so long drove me crazy,” Wuhan resident Tong Zhengkun told AP as he watched celebrations from a bridge across the Yangtze River.

He said his apartment blocked was totally locked down after residents contracted the virus.

Xiao Yonghong and her family were among the residents living elsewhere who ended up stuck in Wuhan in January while visiting for Lunar New Year.

“We were too excited to fall asleep last night. I was looking forward to the lockdown lift very much. I set up an alert to remind myself. I was very happy,” she told AP as she waited for a train home.

Another passenger, Zeng Xiao, spoke to Bloomberg while waiting for a train back to her home in Guangzhou.

“I haven’t seen my cat in almost three months,” the 22-year-old said. “I’m very happy there are finally trains going out.”

Airlines are also taking precautions as they fly people from Wuhan to other parts of China.

“The crew will wear goggles, masks, and gloves throughout the flight,” a chief flight attendant told China’s Xinhua News Agency.

“It will be very smooth because we have made much preparation for this flight.”

But some residents remain cautious.

“I will only feel safe going out in June when the summer heat can kill the virus,” resident Fu Bianlin told Bloomberg.

“The end of quarantine could bring more suspicious risks as more people start moving around.”

On Tuesday alarming photos emerged of about 20,000 sightseers flocking to a popular mountain range in China over the weekend — forcing authorities to shut it down — as the country loosened its coronavirus restrictions.

Photos and videos circulating on the Weibo social media platform show packs of mask-wearing visitors crowding pathways and jostling for space at the Huangshan, or Yellow, Mountains in Anhui province on Saturday and Sunday.

“I think China is keeping a close eye on COVID-19 detections and may need to tune the social distancing measures that are needed to keep COVID-19 contained,” Benjamin Cowling, a professor of epidemiology and biostatistics at Hong Kong University, told the South China Morning Post.

“For now, it may be OK to relax some measures, but those measures should be tightened if case numbers pick up.”