The 76-year-old's civilian government was removed in a coup last year that triggered mass protests, and she faces a raft of charges that could see her sentenced to more than 150 years in jail.

Currently on trial for alleged corruption, breaching Myanmar's official secrets act and pressuring the election commission, Suu Kyi was placed in quarantine last week after Covid was found among her staff.

On Thursday she "appeared before the district judge" for her official secrets act trial in a special court in the military-built capital Naypyidaw, said a source with knowledge of the matter.

Suu Kyi is accused along with Australian economist Sean Turnell, who was arrested in the days following the coup last February.

The charge carries a maximum penalty of 14 years in prison.

Suu Kyi and her personal staff have been fully vaccinated against Covid-19 since being taken into military custody, her lawyer told AFP last July.

She missed a hearing in September due to illness, and in October her lawyer said her health had suffered during her frequent appearances before the junta-run court.

Journalists are barred from the proceedings and her lawyers have been banned from speaking to the press.

Suu Kyi has already been sentenced to a total of six years in jail for incitement against the military, breaching Covid-19 rules and breaking a telecommunications law -- although she remains under house arrest while she fights other charges.