Hong Kong on Tuesday became the second place outside mainland China to report the death of a coronavirus patient as restrictions on movement were imposed in more cities far from the epicentre, including the home of tech giant Alibaba.

The toll on the mainland soared to 425 deaths after 64 more people died, the biggest single day tally since the first fatalities emerged last month.

In a sign of growing concerns about infections rising further in major metropolitan areas, authorities in eastern Zhejiang province limited the number of people allowed to venture outside in three cities.

Three districts in Hangzhou -- including the area where the main office of Chinese tech giant Alibaba is based -- decided to allow only one person per household to go outside every two days to buy necessities, affecting some three million people.

The city is only 175 kilometres southwest of Shanghai, which has more than 200 cases, including one death, so far.

Similar measures were imposed in Taizhou and three districts in Ningbo, with total populations of nine million, days after the same was done in Wenzhou, home to another nine million people.

Zhejiang province has confirmed 829 cases -- the highest number outside the central region of Hubei, whose capital, Wuhan, is the epicentre of the outbreak.

The disease is believed to have emerged in a market in Wuhan that sold wild animals, spreading rapidly as people travelled for the Lunar New Year holiday in late January.

China has struggled to contain the virus despite enacting unprecedented measures, including locking down more than 50 million people in Hubei.

The death of the 39-year-old man in Hong Kong came as the semi-autonomous city closed all but two land crossings with the Chinese mainland to slow the spread of the virus.

Hong Kong media said the man had underlying health issues that complicated his treatment. He had visited Wuhan last month.

Hong Kong has been particularly on edge over the virus as it has revived memories of the Severe Acute Respiratory Syndrome (SARS) outbreak of 2002-03, which killed nearly 300 people in the financial hub and 349 people in the mainland.

With more than 20,400 confirmed infections in China, the mortality rate for the new coronavirus is much lower than the 9.6 percent rate for SARS.

The virus has so far spread to more than 20 countries, prompting the World Health Organization to declare a global health emergency, several governments to institute travel restrictions, and airlines to suspend flights to and from China.

On Sunday the Philippines reported the death of a Chinese man who had come from Wuhan -- the first outside China.

'Shortcomings and difficulties'

China's Communist leadership made a rare admission of fallibility on Monday as it acknowledged "shortcomings and difficulties exposed in the response to the epidemic".

The elite Politburo Standing Committee called for improvements to the "national emergency management system" at the meeting, according to the official Xinhua news agency.

"It is necessary to strengthen market supervision, resolutely ban and severely crack down on illegal wildlife markets and trade," the Politburo said.

The government also said it "urgently" needed medical equipment such as surgical masks, protective suits and safety goggles as it battles to control the outbreak.

Most of the deaths have been in Wuhan and the rest of surrounding Hubei province, which has largely been under lockdown for almost two weeks.

A 1,000-bed field hospital in Wuhan built from scratch within two weeks to relieve overburdened medical facilities started receiving patients on Tuesday. A second makeshift hospital is due to open later this week.

Disabled boy dies while father in quarantine

A disabled boy has died after being left to fend for himself when his father was quarantined over the deadly new coronavirus in China's Hubei province.

Yan Cheng, who was confined to a wheelchair because of cerebral palsy, was abandoned at home when his father was isolated because of a fever.

The 17-year-old, who could not speak, walk or eat by himself, and whose mother died several years earlier, had no one to feed him or help him with daily life.

His father, Yan Xiaowen, was taken into quarantine on January 22, and diagnosed with the potentially deadly virus five days later. He posted a desperate plea for help on social media, calling for someone to go and look after his son.

But the post, entitled "An appeal for help from a father diagnosed with novel coronavirus", came too late.

The teenager died on January 29, according to a statement by the Hongan county government.

"Yan Xiaowen was unable to take care of Yan Cheng's daily life (because of being in isolation)... so he entrusted his relatives, village cadres and village doctors to take care of Yan Cheng," the county government said.

The boy's death has cost senior local figures their jobs. The local Communist Party secretary and mayor were fired because they had "failed to fulfil their responsibilities", officials said. The son's cause of death had yet to be confirmed, they said.

News of the tragedy sparked an outpouring of rage and grief on social media, where authorities in Hubei have already been criticised for withholding information about the infection.