Hundreds waited in grim silence at a Bangkok stadium to get free Covid-19 tests Saturday as a spiraling infection rate gripped Thailand, on a fourth consecutive day of more than 1,000 new cases.

The capital appears to be the epicentre of the kingdom's third wave, after infections were traced back to a nightlife district earlier this month.

Bangkok residents get free Covid-19 tests at a city stadium
Bangkok residents get free Covid-19 tests at a city stadium AFP / Mladen ANTONOV

In the past 10 days, the national infection total has jumped from 29,900 to more than 40,500 -- the sharp increase probably due to a highly infectious variant of the virus originally found in Britain.

"Nearly 10,000 new cases were found within this week," said Taweesin Visanuyothin, a spokesman for Thailand's Covid-19 task force.

A Buddhist monk is sprayed with disinfectant in a special cabin during a mass testing event
A Buddhist monk is sprayed with disinfectant in a special cabin during a mass testing event AFP / Mladen ANTONOV

He added that nearly 12,000 patients were still receiving treatment in hospitals, including temporary field sites.

At the stadium testing centre, health workers in full-body PPE shepherded people through a disinfection cabin, and directed them to wait in lines for the nasal swab.

New restrictions will bite from Sunday, including an alcohol ban in restaurants and bars
New restrictions will bite from Sunday, including an alcohol ban in restaurants and bars AFP / Lillian SUWANRUMPHA

The site -- one of many testing centres across the city -- has capacity to screen up to 3,000 people per day, for free under the kingdom's social security programme.

"I think this outbreak will be protracted because (the UK variant) spreads fast," said one woman who received the test, adding that she was worried about going outside.

Authorities have instated inter-provincial travel restrictions right before Songkran new-year festivities this week -- usually a period when Thais vacation or return to their hometowns.

The typically rowdy holiday is also marked by water fights on the streets, but Bangkok was quiet this week -- with bars, restaurants and night markets closed early.

New restrictions will bite from Sunday, including an alcohol ban in restaurants and bars, while entertainment venues will be shuttered across the country for two weeks.

Political opponents of Premier Prayut Chan-O-Cha have criticised his administration's handling the virus, and the slow roll-out of the vaccine -- which has been plagued by delays.

By Saturday, 605,000 doses of both Sinovac and AstraZeneca vaccines had been administered.

Coronavirus