Australia's government on Thursday rejected a Myanmar court's sentencing of economist Sean Turnell to three years in jail and demanded his "immediate release".
Foreign Minister Penny Wong criticised the ruling against Turnell, an Australian citizen, saying he was tried in a closed court with no consular access.
Australia will "advocate strongly" for Turnell until he is returned to his family, Wong said, after the academic was imprisoned under the Official Secrets Act.
Detained since Myanmar's coup in February last year, Turnell was previously an adviser to ousted leader Aung San Suu Kyi's government.
Australia has contested the charges during the 19 months that Turnell has been "unjustly detained by the Myanmar military regime", Wong said.
"The Australian government rejects today's court ruling... and calls for his immediate release," she added.