The Public Health Ministry will on Monday tell Bangkok Governor Chadchart Sittipunt to limit public activities to minimise a possible coronavirus resurgence.
Kiattiphum Wongrajit, permanent secretary for public health affairs, said on Sunday he will call for the Bangkok Metropolitan Administration (BMA) to reduce the number of events drawing large crowds.
Dr Kiattiphum said figures showed government hospitals in the capital should brace for a swell of new Covid-19 patients.
About 2,000 people a day are now being treated in hospitals, more than half of them in Bangkok, he said. Worse, 42% of coronavirus inpatients in the capital are seriously ill or showing life-threatening symptoms, he continued.
Dr Kiattiphum said Governor Chadchart chairs the communicable disease committee in Bangkok, and thus has the authority to issue any health measures needed.
The public health secretary did not specify the events he considered highly likely to spread Covid-19.
The latest government manoeuvre is likely to be viewed as politicking, given its waning popularity, its perceived inability to address the Covid-19 pandemic and the landslide election of the former Pheu Thai heavyweight to lead the nation's capital.
Mr Chadchart has initiated several programmes to restore life to Bangkok, including open-air movies and concerts in public parks.
Dr Kiattiphum's position reflects growing worries about a possible spike as doctors and health personnel have warned of the danger of two new subvariants, BA.4 and BA.5, due to their high transmission.
Although the country has low fatality numbers - rising from the 17 reported on July 4 to 18 reported on Saturday - the number of people seriously ill has risen.
The number of patients in serious condition increased from 677 to 785 and those relying on ventilators rose from 299 to 352 during the same period, the ministry's latest figures released on Sunday showed.
Prime Minister Prayut Chan-o-cha was concerned about the possibility of the coronavirus spike and urged people returning from family visits and vacations during the five-day holiday to monitor their health, government spokesman Thanakorn Wangboonkongchana said on Sunday.
People returning from vacation who develop symptoms resembling those of Covid-19 should conduct an antigen test before they return to their workplaces, the spokesman said.
They should stay at home and avoid public places if they test positive, he added.