A stay-at-home order has taken effect across Yangon, Myanmar's biggest city, after the country reported a record-high number of new Covid-19 cases, just weeks before its November elections.

The region's more than four million people had less than 24 hours to prepare for the order, which came into effect at 8 am (01:30 GMT) on Monday morning.

It requires most private-sector employees to work from home and government staff to work on a rotation of two weeks at home and two weeks at the office. Schools had already been closed under previous lockdown measures.

Health Minister Myint Htwe said the measures were necessary because of the rise in locally-transmitted cases that were not the result of travel or contact with anyone already known to have the disease.

Under the new rules, people must stay at home unless they need to buy food or visit a doctor. Anyone who does go out must wear a face mask, and only one member of each family is allowed to go shopping for essentials. No one is allowed to travel outside the Yangon region.

It was not clear what support there would be for people unable to work from home or in informal jobs.

No exaggeration to say next 2 weeks critical for Myanmar’s future. If Yangon lockdown doesn’t work and virus spread accelerates, Myanmar could face combined health & (if lockdown continues) economic disaster; given country’s other challenges, anyone’s guess where that might lead.

— Thant Myint-U (@thantmyintu) September 21, 2020

I've been checking @nyeinchamkoko's COVID Myanmar dashboard religiously the past week as cases climb in Yangon. Hope everyone is safe! https://t.co/sgrRshroNJ pic.twitter.com/uvl4B9rdOv

— Yan (@yanoak) September 21, 2020

Essential services such as banks, petrol stations and food outlets would continue to operate, the authorities said.

The health ministry said on Sunday it had recorded 671 new coronavirus cases, without saying where. Myanmar recorded no locally transmitted cases of coronavirus for weeks until the disease suddenly re-appeared in the conflict-hit western state of Rakhine. Most of the recent cases have been in Yangon.

Myanmar has so far reported a total of 5,541 COVID-19 cases and 92 deaths.