The exact details of his alleged offence have not been made public, though state television said he had access to "secret state financial information" and tried to flee the country
An Australian adviser to Myanmar's ousted leader Aung San Suu Kyi appeared in a junta court to face immigration and official secrets charges, a lawyer involved in the case said Thursday.
Macquarie University professor Sean Turnell was the first foreign national arrested following the February 1 coup that ousted Suu Kyi's government and sparked huge protests.
Turnell has been held at Insein Prison in Yangon since his arrest and appeared "frail and tired" in court in the capital Naypyidaw, said lawyer Khin Maung Zaw, who is working on the case.
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 Turnell allegedly receiving a vaccine in Insein Prison later appeared in state-run media.
The exact details of his alleged offence have not been made public, though state television has said he had access to "secret state financial information" and had tried to flee the country.
The judge who will hear Turnell's case, Ye Lwin, presided over the trial of two Reuters journalists arrested while reporting on a September 2017 massacre of 10 Rohingya Muslims in conflict-hit Rakhine state.
Wa Lone and Kyaw Soe Oo were later sentenced to seven years in jail, sparking an international outcry.
The pair were freed 16 months later in an amnesty.
David Mathieson, an analyst formerly based in Myanmar, said the proceedings against Turnell would be little more than a "show trial".
Myanmar has been in turmoil since the military putsch, which sparked a mass uprising and a brutal crackdown on dissent.
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 government was deposed by the military for alleged voter fraud during 2020 polls, in which it trounced a political party aligned with the generals.
Security forces have killed more than 1,100 civilians since the coup, according to a local monitoring group.
The military says the toll is much lower.