Myanmar citizens face serious problems with medical treatment and supplies in part because of the crackdown by the junta as COVID-19 case numbers appear to be growing.

Residents across the coup-hit country's biggest city of Yangon defied a military curfew in a desperate search for oxygen to keep their loved ones with COVID-19 breathing, according to reports.

Residents told AFP they had slipped out in the dead of night to secure spots in lines to refill oxygen cylinders - dismissing claims from the country's military rulers that there is more than enough to go around.

Medical treatment in Myanmar is patchy and even before the coup and the COVID-19 pandemic the country was not known for good health care – those who could afford it typically flying to neighbouring Thailand where facilities are first class.

It is unclear what type of treatment is provided for people suffering with symptoms of COVID-19. There are effective treatment regimens for those caught in the early stage of the disease. Oxygen is typically prescribed for those with serious symptoms.

Currently, what is also unclear is how much testing is being done with the PCR test, a notoriously ineffective way to test for COVID-19.

Worldwide, as the virus shows little sign of easing, the World Health Organization (WHO) is working towards the second phase of an investigation into where COVID-19 originated and urged China on Thursday to better cooperate.

WHO chief Tedros Adhanom Ghebreyesus demanded more access to raw data after a report compiled by a team of independent experts in Wuhan earlier this year was widely criticised for lack of transparency and access.

Claims of origin vary from a natural cause to the virus being made in a lab and accidently or deliberately being leaked.