The Department of Disease Control estimates the latest wave could see a record-breaking 30,000 new cases per day in a worst-case scenario.
Such levels of Omicron-fuelled infection would overwhelm hospital capacity, which stands at 52,300 beds across the whole country and 25,828 in metropolitan Bangkok.
A surge in cases would trigger a switch to Home Isolation (HI) and Community Isolation (CI) as the first line of treatment. Only severe cases would then be sent to hospitals, said Dr Somsak.
He also predicted a high infection rate among children, most of whom have not been vaccinated. However, most infected children would escape severe symptoms unless they had underlying disease, he added.
The Bangkok Metropolitan Administration (BMA) is preparing Community Isolation beds for children and families in six zones, with at least 50 beds per site.
Somsak also called on the Queen Sirikit National Institute of Child Health to prepare stocks of antiviral favipiravir to treat children across the country.