Chinese President Xi Jinping assured his US counterpart on Friday that China was doing all it can to contain a new coronavirus that has killed almost 640 people, including a doctor who sounded the alarm only to be threatened by police.

China was gradually achieving results and was confident it could defeat the epidemic with no long-term consequences for economic development, Xi told President Donald Trump in a telephone call, according to state television.

Trump, after the phone conversation with the Chinese president said that Beijing is showing “great discipline” in tackling the coronavirus outbreak.

“Nothing is easy, but he will be successful, especially as the weather starts to warm & the virus hopefully becomes weaker, and then gone,” Trump said on Twitter

“Great discipline is taking place in China, as President Xi strongly leads what will be a very successful operation. We are working closely with China to help!”

The call to the White House, which China has accused of scaremongering over the epidemic, came as China's central bank vowed to step up support for the economy to cushion the blow of the outbreak.

First-quarter growth in the world's second-biggest economy could slow by 2 percentage points or more, from 6 per cent, in the last quarter, analysts say, but could rebound sharply if the outbreak peaked soon.

Chinese stocks were heading for their worst week since May while elsewhere in Asia, financial markets slipped after several days of gains.

Xi had earlier declared a “people's war” on the virus, saying China had responded with all its strength and “the most thorough and strict prevention and control measures”, state media said.

The rallying cry came amid an outpouring of grief and anger on social media over the death of ophthalmologist Li Wenliang.

Li, 34, was one of eight people reprimanded by police in the central city of Wuhan, the epicentre of the contagion, last month for spreading “illegal and false” information about the flu-like virus.

His social media messages warning of a new “SARS-like” coronavirus — a reference to Severe Acute Respiratory Syndrome (SARS) which originated in China and killed almost 800 people around the world in 2002-2003 — triggered the wrath of police.

China was accused of trying to cover up SARS.

Li was forced to sign a letter on January 3 saying he had “severely disrupted social order” and was threatened with charges.

“We deeply mourn the death of Wuhan doctor Li Wenliang ... After all-effort rescue, Li passed away on 2:58am,” the ruling Communist Party's People's Daily said on Twitter.

Data watch

Many social media users described Li as a hero, accusing authorities of incompetence in the early stages of an outbreak that has now claimed more than 400 lives in Wuhan.

“Light a candle and pay tribute to the hero,” one person posted on the Weibo platform.

Some media outlets described Li as a hero “willing to speak the truth” but there were signs that discussion of his death was being censored.

The death toll in mainland China reached 636 with 73 more deaths recorded as of Thursday, and 3,143 new confirmed infections, taking the total to 31,161 cases, the National Health Commission said.

The 3,143 new infections were down from Wednesday's figure of 3,694 and 3,887 on Tuesday, but experts warned it was too early to say if the data represented a trend.

The virus has spread around the world, with 320 cases in 27 countries and regions outside mainland China, according to a Reuters tally of official statements.

Two deaths have been reported outside China, in Hong Kong and the Philippines, but uncertainty about how deadly and contagious the virus is has prompted countries to quarantine hundreds of people and cut travel links with China.

At sea

There were 41 new cases among about 3,700 people quarantined in a cruise ship moored off Japan, for a total of 61 cases on board.

In Hong Kong, a cruise ship with 3,600 passengers and crew was quarantined for a third day after three people who had been on board were found to be infected.

Taiwan, which has 16 cases, banned international cruise ships from docking.

Britain confirmed a third case in which the coronavirus was contracted after the individual concerned visited an Asian country other than China. The government did not identify the country but issued a list of places from which travellers who developed symptoms should isolate themselves, it said.

The list included Hong Kong, Japan, Macau, Malaysia, Singapore, South Korea, Taiwan and Thailand, as well as China.

China has chafed at some travel curbs imposed by other countries, which the WHO says are unnecessary.

The capital of Beijing resembles a ghost town, with main thoroughfares and tourist spots almost deserted, as the country has sealed off cities, cancelled flights and closed factories, cutting supply lines to global businesses.

Record low prices for liquefied natural gas were roiling the global gas market, while the virus was also throwing the global container shipping trade out of sync, with lines re-routing cargoes and reducing calls to Chinese ports, setting the scene for months of delivery delays, industry sources said.

Foreign investors are also counting the cost.

Toyota Motor Corp and Honda Motor Co extended suspensions of production at Chinese plants, joining a growing number of automakers facing stoppages due to supply-chain disruptions.

South Korea asked Chinese authorities for help to resume production at South Korean suppliers of auto parts. Japan's Fast Retailing, which runs clothing chain Uniqlo, said it had temporarily closed about 370 of its 750 shops in China.