Myanmar's spiralling coronavirus count struck the trial of ousted leader Aung San Suu Kyi on Monday, her lawyers said, with a witness for the prosecution failing to testify after becoming infected.

Cases are spiking in Myanmar, with the State Administration Council -- as the military junta calls itself -- reporting more than 3,400 new cases Sunday, up from fewer than 50 per day in early May.

Suu Kyi was deposed by the military in February, sparking a mass uprising and a brutal crackdown. More than 890 civilians have been killed by the junta's forces, according to a local monitoring group.

On Monday, a prosecution witness set to testify that she violated coronavirus restrictions during elections her party won in a landslide last year "was absent on account of COVID-19 infection", her lawyer Khin Maung Zaw told reporters.

A second witness gave testimony on the same charges, and the court also heard evidence on separate charges that Suu Kyi illegally imported and possessed walkie talkies, he said.

The Nobel laureate, 76, and all members of her staff have been fully vaccinated while in military custody, her lawyer Min Min Soe told reporters last week.

She did not give details on when Suu Kyi -- who is believed to have received a first dose before her government was deposed -- had received the jab, or what vaccine she was given.

The ousted leader "voiced her grave concern for the people during the third wave of Covid-19" during Monday's pre-trial meeting, Khin Maung Zaw said.

Suu Kyi and former president Win Myint -- who also faces charges of breaking COVID-19 restrictions -- both appeared in good health, he added.

Cut off from the outside world except for brief meetings with her legal team and her court appearances, Suu Kyi faces a raft of charges that could see her jailed for more than a decade.