Chau Van Kham, who opposed the communists during the Vietnam War, was sentenced to 12 years in prison in November 2019, after being arrested while on a fact-finding tour of Vietnam.

“We share this happy news that Mr Chau Van Kham is well and has returned to his family today,” his solicitor Dan Phuong Nguyen said in a statement sent to AFP.

The retired baker, who had been reunited in Australia with his wife and two children, thanked well-wishers and the Australian government for its support, Nguyen said.

“However, the family asks for privacy at this emotional time of reunion.”

The dissident, 74, had been sentenced for “terrorism against the People’s Administration”.

He was in the country to conduct human rights research and meet with activist and civil society contacts, his lawyers told AFP in Hanoi at the time.

Kham has been a member of the banned anti-government Viet Tan group since 2010.

It is run by members who are mostly overseas since Hanoi designated it a terrorist organisation in 2016, accusing it of “instigating violence”.

Viet Tan denies the claim and says it “advocates for social justice and democratic change through peaceful means”.

Kham is a former Navy serviceman who fought on the side of the South during the Vietnam War, fleeing on a boat in 1983 after the fall of Saigon – now called Ho Chi Minh City – and eventually settling in Australia.

Communist Vietnam frequently jails its critics, and a conservative regime in power since 2016 has cracked down on activists in the one-party state.