Vietnamese authorities have detained three activists, including an Australian, on what have been described as “fabricated” charges.

The Vietnamese government said the three confessed to being members of Viet Tan – a pro-democracy organisation – which it describes as a terrorist organisation.

In a statement, Viet Tan said it “strongly condemns the abduction of two of its members in Cambodia and the fabricated charges issued by the Vietnamese communist authorities to cover up an act of transnational repression”.

It is not clear if the third person is a Viet Tan member as well.

Tran Hiep, a 50-year-old Vietnamese Australian democracy campaigner, was due to return to Bangkok, Thailand, to reunite with his wife, Chloe Dang, after a short trip to Phnom Penh, Cambodia, to meet with human rights defenders.

Earlier, his wife implored the federal government to find him and bring him home after he failed to board his flight.

He had not communicated with his wife since 18 September, leaving her worried for his safety.

“My family and I are really worried about his safety, and we just only want to know where he is and what happened to him,” Dang said from Bangkok airport before boarding a flight to Melbourne.

“My husband deserves protection, and I really hope the Australian government will continue to put pressure on Cambodia to do an investigation to find out where he is right now.”

Hiep, a freelance IT professional who founded the Australian Alliance to Combat Human Trafficking, was travelling with another human rights activist Nguyen Duc Thuan, who is also Vietnamese and holds a Norwegian passport.

The pair travelled to Cambodia to meet with dissident Vietnamese activists for training.

Viet Tan says it aims to “overcome dictatorship and build the foundation for a sustainable democracy”, and that it was “committed to peaceful, nonviolent struggle”.

“We are convinced that nonviolent means are most effective for generating maximum civic participation,” the organisation said on its website.

Human Rights Watch has previously described Viet Tan as “an opposition political party … which operates openly and lawfully in many countries including Australia, but which Hanoi arbitrarily labels ‘terrorist’.”

Vietnam in recent years has ramped up its crackdown on dissidents, with more than 55 activists arrested under broad criminal laws in 2025.

On 18 September, Human Rights Watch said more than 160 political prisoners were currently locked up in Vietnam, and that activists faced “police harassment, intimidation, surveillance, and interrogation on a daily basis”.

Viet Tan urged the Norwegian and Australian authorities to ask for access to the Hiep and Thuan, to “ensure their wellbeing and access to needed medication”.

It said the pair had “no intention” of entering Vietnam and the claim they had done so illegally was a “blatant fabrication” to cover up their abduction.

“Viet Tan is particularly concerned that To Lam’s police state is using its security apparatus to pursue and repress activists and foreign nationals even beyond Vietnam’s borders,” it said.

“Meeting with, exchanging ideas with, and supporting human rights defenders, democracy activists, and civil society is a peaceful form of advocacy to advance freedom, democracy, and human rights in Vietnam.”

Civil society groups and United Nations human rights experts have repeatedly warned of growing cooperation between Vietnamese authorities and neighbouring governments targeting advocates.

Viet Tan, a pro-democracy diaspora political party, had earlier described the pair’s disappearance as concerning given previous cases involving Vietnamese dissidents vanishing in neighbouring countries and subsequently appearing in custody in Vietnam.

“Their disappearance is not an ordinary ‘missing person’ incident. Both men are longtime human rights advocates and Viet Tan members,” the organisation said.

Dang, 36, said fretting over her husband’s whereabouts had taken a psychological toll.

“It’s been 11 days and I’m really in the dark,” she said, choking back tears.

“I don’t know where he is and how he’s doing – it’s driving me crazy.

“Everything is really uncertain.”

The Australian government confirmed consular officials were in contact with Dang but declined to comment further.

“The Department of Foreign Affairs and Trade is providing consular assistance to the family of an Australian reported missing in Cambodia,” a department spokesperson said on Monday.

The families of the missing men have filed an appeal with the UN working group on enforced or involuntary disappearances.