YANGON (AFP) - An Australian adviser to Myanmar's ousted leader Aung San Suu Kyi appeared in a military court to face immigration and official secrets charges, a lawyer involved in the case said on Thursday (Sept 23).

Macquarie University professor Sean Turnell was the first foreign national arrested following the Feb 1 takeover that ousted Ms Aung San Suu Kyi's government and sparked huge protests.

Prof Turnell has been held at Insein Prison in Yangon since his arrest and appeared "frail and tired" in court in capital Naypyidaw, said lawyer Khin Maung Zaw, who is working on the case.

Prof Turnell was wearing a "full Covid-19 protective outfit", the lawyer added, without giving precise details.

In July, his wife pleaded for his release, citing worries about his health as the country endured a surge of Covid-19 cases.

Pictures of the professor allegedly receiving a vaccine in Insein Prison later appeared in state-run media.

Myanmar has been in turmoil since the military putsch, which sparked a mass uprising and a brutal crackdown on dissent.

Ms Aung Suu Kyi is on trial for a raft of offences, including illegally importing walkie-talkies, flouting coronavirus rules and incitement.

She faces decades in prison if found guilty.

Her National League for Democracy (NLD) government was deposed by the military for alleged voter fraud during 2020 polls, in which the NLD trounced a political party aligned with the generals.

Security forces have killed more than 1,100 civilians since the military takeover, according to a local monitoring group.

The military says the toll is much lower.