Thai volunteers on Wednesday turned a cargo warehouse at Bangkok's Don Muang Airport into a 1,800-bed field hospital for Covid-19 patients with less severe symptoms, as the country deals with its biggest outbreak to date.

The Southeast Asian nation reported a daily record of 16,533 new cases, plus 133 new deaths on Wednesday, bringing the total accumulated cases to 543,361 and 4,397 deaths.

Workers drilled walls for toilet installations and set up beds and blankets. "This is a level 1+ field hospital where it can receive a large number of patients, who have less severe symptoms," Rienthong Nanna, director of Mongkutwattana Hospital, told Reuters. "But if patients' conditions deteriorate, they will be moved to our other field hospital called Pitak Rachan (Protect the King) Field Hospital," he added.

Rienthong, a retired major-general and an ultra-royalist leader, said the field hospital was not up and running yet as more preparations were needed.

The number of infections will continue to climb and more field hospitals will be needed, he added. Rienthong and volunteers held a small ceremony on the occasion of King Maha Vajiralongkorn's 69th birthday to unofficially inaugurate their third field hospital named "Tai Rom Prabaramee", which means "under the glory of His Majesty".