Covid-19 infections at construction sites continue to escalate after a new cluster of 519 infected workers was reported near the parliament complex in Nonthaburi. Bangkok Post

Workers who tested negative for Covid-19 in isolation inside living quarters owned by Sino-Thai Engineering & Construction Plc in Bangkok on Monday. (Photo: Pornprom Satrabhaya)

Covid-19 infections at construction sites continue to escalate after a new cluster of 519 infected workers was reported near the parliament complex in Nonthaburi.

Most of the workers were migrants employed by Sino-Thai Engineering and Construction Pcl on Phibul Songkhram Road in Muang district. The news came after 900 of the site crew were tested on May 22.

Nonthaburi Muang district chief Phirun Wimon-akson said he would ask the province to temporarily close the construction site last night with the infected Thai workers sent to field hospitals in the province and the foreign contingent staying on site for treatment at a field hospital which is being set up there.

Sukij Atthopakon, the adviser to the parliament president, said he was told that none of the infected workers had entered parliament at any time since the work began.

More construction sites were also put under quarantine, as Bangkok's Bang Phlat district director Panchaphat Lakdee on Monday ordered a camp on Rung Pracha Road closed with the workers barred from leaving the premises.

Labour Minister Suchart Chomklin said all the labourers were fully documented and would be properly treated, adding that swift action was being taken now as more and more cases were being diagnosed at such sites.

The Labour and Interior ministries will inspect a further 393 camps in Bangkok, he said.

Meanwhile, in Phetchaburi, another field hospital with 2,400 beds has been set up at the Cal-Comp Electronics factory in Khao Yoi district as cases mount in another cluster of Covid-19 infected workers.

The factory on Monday reported 678 new infections, bringing the cumulative total to 2,789. There are now two field hospitals with a total of 4,800 beds at the factory.

Local public health authorities have suggested that all large businesses in Khao Yoi should prepare space for field hospitals in case they suffer from an outbreak.

Every infected worker at the Cal-Comp factory was ordered to report to disease control officers by the end of the day on Monday or face the threat of legal action. Those workers who have been ordered into quarantine will continue to receive their usual salaries, authorities said.

Assistant spokesperson for the Centre for Covid-19 Situation Administration (CCSA) Apisamai Srirangson said the Bangkok Metropolitan Administration's Public Works Department had asked the CCSA to invite 134 construction companies in Bangkok to send a representative to a briefing on the necessary steps to take with regards to housing a large number of migrant workers during the pandemic.

The CCSA earlier asked all those businesses responsible for large camps of foreign workers to step up disease prevention measures with a particular focus on eating areas, common areas and the transportation of groups of workers.

"District offices have the power to close camps that are not being properly managed," Dr Apisamai said.