The Chinese capital, Beijing, is capable of screening almost 1 million people a day for the novel coronavirus, an official said on Sunday, as testing continued across the city to try to contain the spread of a fresh outbreak.

Beijing has been expanding testing in the city of 20 million since a cluster of infections linked to a food wholesale market erupted over a week ago.

The outbreak, the first in Beijing in months, has now surpassed previous peak numbers in the city in early February.

Testing was initially focused on people who worked or shopped at the Xinfadi market or lived nearby but it has been expanded to include residents in many other parts of the city as well as food and parcel delivery workers.

Since the new outbreak, capacity has more than doubled to more than 230,000 tests daily at 124 institutions, Gao Xiaojun, spokesman for the Beijing Health Commission, told a press briefing.

The tests are done on samples collected from multiple people in one test tube, meaning the city can get results from almost 1 million people daily, he added.

The same pooling of samples was also carried out in Wuhan last month to quickly ramp up daily testing capacity after a cluster of new cases there raised worries about a second wave of infections.

Gao also said that provinces including Hubei and Liaoning had sent about 200 people to Beijing to boost staff in laboratories, further helping to increase testing capacity.