Police have arrested a Cambodian polygamist and his two wives for trading Vietnamese virgins in a scam that indicates a new trafficking route has emerged across three Asian countries, authorities said on Monday.

Police said four girls, one was acquired for 75 dollars along with another six Vietnamese women were smuggled from Vietnam to Cambodia where they were to receive fake passports while being held in a Phnom Penh brothel. They were then to be sold to brothels in Malaysia.

A senior police official told AFP that Khieu Khem, 40, was arrested along with his two wives aged 28 and 42 were expected to appear in court shortly, where they would face formal charges. It was the third time in three months that traffickers have been arrested while en-route to Malaysia, police said.

A Vietnamese passport holder requires a visa for entry to Malaysia, Cambodians do not, and police say there are signs Vietnam to Malaysia via Cambodia has emerged as a new route for human traffickers due to the visa requirements. The police official said the four girls were aged between 13 and 15, while the women were between 20 and 22 years-of-age.

"Our investigations prove that this group of people have taken Vietnamese girls to Malaysia before, this is their second attempt and we have arrested them," the police official said.

In recent years, many Vietnamese women were trafficked to Cambodian brothels. In mid-April, Vietnamese police in Ho Chi Minh City detained two women on suspicion of trafficking dozens of Vietnamese virgins to Cambodian brothels for less than 350 dollars each.

After the girls lost their virginity in Phnom Penh and other cities, a butterfly was tattooed onto their stomachs to mark their lower value. In its annual report, Save the Children reported two weeks ago that 35 per cent of Cambodian sex workers were under 18-years-old and nearly half were infected with the HIV virus.