China on Wednesday said it has more than 1,300 asymptomatic coronavirus cases, the first time it has released such data following public concern over people who have tested positive but are not showing symptoms.

Health officials also reported the first imported case from abroad in Wuhan -- the epicentre where the virus first emerged late last year -- heightening fears of infections being brought into China from other countries.

Of 36 new cases reported Wednesday, 35 were imported from abroad. The National Health Commission (NHC) said 1,367 asymptomatic patients were under medical observation, with 130 new cases newly added in the last day.

The NHC announced Tuesday that it would respond "to public concerns" by starting to publish daily data on asymptomatic cases, which it said were infectious.

There were mass online calls for the government to reveal the number of asymptomatic cases after authorities revealed over the weekend that an infected woman in Henan province had been in close contact with three asymptomatic cases.

However, asymptomatic cases are not being added to the official tally unless they later show clinical symptoms. Historical data on those infected without showing symptoms has not been published.

Beijing has announced a series of dramatic measures to curb arrivals into the country and control imported cases -- including a ban on foreigners entering China and testing those arriving from overseas -- making it easier to determine those who are infected but don't show symptoms.

China says all detected asymptomatic cases and their close contacts must undergo 14-day centralised quarantine. Experts agree that asymptomatic patients are likely to be infectious, but it remains unknown how responsible they are for spreading the deadly virus.

Chinese respiratory expert Zhong Nanshan said in a state media interview last week that asymptomatic carriers could potentially infect "3 to 3.5 people each".

Many other countries including South Korea and Japan count asymptomatic cases in their national tallies of confirmed diagnoses.

There have now been 81,554 infections in China, with 3,312 deaths -- mostly concentrated in the epicentre of Wuhan and surrounding Hubei province.

The first imported case confirmed in Wuhan, a Chinese national studying in Britain, arrived in the city last week as it starts to gradually lift travel restrictions imposed to control the outbreak.

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