Pro-democracy group Viet Tan is calling for the Australian government to question its relations with Vietnam after Hanoi jailed a retired Sydney baker for 12 years on terrorism charges in a "sham" trial.
Chau Van Kham, 70, was sentenced alongside Nguyen Van Vien and Tran Van Quyen over allegations he had raised money for anti-state activities, joined anti-Vietnam protests in Australia and recruited members for the US-based Viet Tan.
"The verdict calls into question communist Vietnam's legitimacy and whether Australia, the United States or any law-abiding nation can forge a sustainable economic or security partnership with Hanoi," Viet Tan chairman Do Hoang Diem said on Tuesday.
Australia signed a strategic partnership with Vietnam focused on defence co-operation, a delicate subject given Beijing's maritime expansion across sea lanes and islands also claimed by Vietnam and Australia's reliance on exports to China.
Kham, of Vietnamese origin, joined Viet Tan, which is outlawed as a terrorist group in Vietnam, about nine years ago and has been an outspoken critic of communist Vietnam.
In recent years, Viet Tan has rejected violence and advocates non-violent reform.
Diem said Kham had travelled to Vietnam to study the country's human rights situation. His colleagues were peaceful activists, Diem said, adding the "arbitrary verdict confirms that legal proceedings in Vietnam are a sham".
"We challenge the Vietnamese government to provide any evidence linking them to 'terrorism'. The Vietnamese authorities are criminalising human rights advocacy," Diem said.
According to a police report, Kham entered Vietnam from Cambodia in January and gave $US400 to help fund Viet Tan operations, which was "a very serious case of national security infringement led by Viet Tan's key people".
Police said Kham was a navy veteran of the former South Vietnam who sought asylum in Malaysia in 1975. He moved to Australia in 1983.
"After nearly a year of arbitrary detention, reports of forced confessions and access to legal counsel granted just 18 days prior to the trial, Vietnamese authorities presented no evidence of 'terrorism' in sentencing the three human rights activists," Diem said.
In Sydney, Kham's wife, Quynh Trang Truong, has appealed to Prime Minister Scott Morrison, saying she was "filled with both faint hopes and great despair" and said her husband was not guilty of the charges.
Viet Tan said that since 2017, Vietnam had arrested dozens of bloggers and human rights defenders in an unprecedented crackdown on free expression that includes posting content on Facebook and taking part in peaceful protests.
It said Kham was convicted in a closed trial, which was a violation of international law.
"Viet Tan demands the immediate and unconditional release of all political prisoners and will continue to highlight the Vietnamese government's ongoing human rights violations," it said in a statement.