Advocacy group Human Rights Watch is calling on the federal government to put pressure on Vietnam to drop charges against four asylum seekers who were returned to the country by Australia.
They will face court in the Vietnam's Binh Thuan province on Thursday, and if convicted, they face a maximum penalty of seven years in prison.
They were charged in August for “organising for others to flee abroad illegally” under article 275 of the country's penal code.
The case stems from incidents last year where the Australian navy intercepted two asylum seeker boats and returned passengers to Vietnam.
Human Rights Watch's Australian director Ms Pearson told SBS News Vietnam was breaking international law.
"The right to leave any country, including one's own, is enshrined in the Universal Declaration of Human Rights," she said.
"It's also in the International Covenant on Civil and Political Rights, both of which have been ratified by Vietnam and both of which are also important to the Australian government.
"We absolutely think this is not a case of people smuggling. There is no evidence that's been alleged that these people profited or in any way coerced other people to come to Australia."
Australian border officials testified in May 2015 before an Australian Senate Estimates Committee that the Australian government had been provided written assurance that these asylum seekers would face “no retribution for their illegal departure from Vietnam".
Ms Pearson said the Australian government should step in to place pressure on Vietnam to drop the charges.
“Imprisoning desperate people trying to leave their own country is cruel as well as unlawful,” Ms Pearson said in a statement.
“The Vietnamese government loses nothing by letting these people go, and Australia should press Vietnam to do so.”