An Australian adviser to deposed Myanmar leader Aung San Suu Kyi is to be placed on trial for allegedly violating state secrets, a source familiar with the proceedings has revealed.

Economist Sean Turnell has been in detention since February 6 last year, a few days after a coup against Suu Kyi’s elected government. He faces up to 14 years in prison if found guilty.

He is expected to be tried alongside Suu Kyi, 76, and several members of her economic team indicted for the same offence.

“Sean was charged under the Official Secrets Act yesterday,” said the source, who declined to be identified because the trial is being held behind closed doors, with information restricted.

“The charge relates to the allegation that he had government documents.”

A military spokesperson could not be reached for comment.

Australia’s foreign minister Penny Wong in a statement said Canberra rejected the court’s decision.

“We will continue to advocate for Professor Turnell’s interests and wellbeing and will not stop until he is safely back with his family,” she said.

Turnell, an economics professor at Sydney’s Macquarie University, had for several years been advisor to Nobel laureate Suu Kyi, who is charged with at least 20 mostly corruption-related offences.

They are among thousands arrested under the junta, including politicians, lawmakers, bureaucrats, students and journalists.

The courts have dealt harshly with opponents of the military, handing down prison terms and even the death penalty after what rights groups say were unfair trials.

The junta insists Myanmar’s courts are independent and those arrested are receiving due process.

-AAP