TAIPEI • More than 300 coronavirus-positive people have gone missing in Taiwan, sparking fears of more clusters as the island's cumulative infections top 6,000.

As at Tuesday, 146 people in Taipei and 164 people in New Taipei City remained uncontactable after their Covid-19 tests turned out to be positive, said Taiwan's Health Minister Chen Shih-chung.

The missing people had been sent home to wait for their results after taking their swab tests. But hospitals have been unable to contact them because the phone numbers and addresses they gave were either fake or illegible, the South China Morning Post reported.

Mr Chen said these people must be located quickly to prevent them from spreading the disease.

The challenges facing the authorities battling a new outbreak are compounded by a backlog at overstretched testing facilities, as people suspected of having Covid-19 have to wait up to nine days for a confirmed result.

The number of people seeking Covid-19 tests has sharply increased over the past two weeks, stretching testing facilities which are now struggling to keep up, data from the Taiwan Centres for Disease Control indicates. This has led to frequent delays between when possible cases are first reported and when results are made available.

Taiwan's government has decided to report a case based on when a test was taken - rather than when there was a result - leading to daily revisions of total infection numbers in recent days.

While the intention is to keep the data as accurate as possible, it leaves officials with a less-than-perfect overview of how the case curve is developing and whether current virus-related restrictions are having any impact - making formulating effective policy more difficult.

The Health Ministry reported an additional 302 new domestic infections and 11 deaths yesterday, bringing Taiwan's total local cases to 4,918 and deaths to 46 since the pandemic began. There were also two imported cases.

Officials also added a further 331 backdated cases stretching as far back as May 17. The ministry says the delays are caused by transporting samples, laboratory capacity and reporting of results.

A total of 6,091 cases, including 1,120 imported ones, have been recorded so far.

Taiwan has seen an increase in domestic cases and is at its second-highest alert level, restricting gatherings and shutting down entertainment venues. Yesterday, it tightened curbs further, including banning dining in at restaurants.

"Go out less and buy more," Mr Chen said.

BLOOMBERG, REUTERS