Vietnam has lodged an official protest with Malaysia after a Vietnamese woman was reportedly sold at a market in a Malaysian town, reports say.
More traditional goods are usually on sale in Malaysia
The Vietnamese ambassador in Malaysia has requested Malaysia's help in identifying the woman, said to be 21.
Malaysian media reported that a 60-year-old man paid some $5,000 (£2,700) for her, possibly as a bride.
Reports said she had run out of money in Malaysia and offered herself for sale as a means of raising some cash.
Ha Thi Khiet, chair of Vietnam's women's union, has also written to her Malaysian counterpart describing the reports as "offensive towards women's honour and dignity".
According to a report in Malaysia's Guang Ming newspaper, a Chinese-language publication, the woman offered herself for sale at a market in the village of Gombak, near the capital, Kuala Lumpur.
She was accompanied by a 40-year-old man who offered her for sale, the AFP news agency reported.
She was eventually sold after a four-hour auction.
There was no confirmation whether the woman was sold as a bride, but a spokesman for Vietnam's foreign ministry insisted that Vietnamese women were not allowed to marry foreigners against their will.
"Marriage must be made on the basis of voluntariness and adherence to Vietnamese law and the resident country's law," Le Dung said.
"All actions relating to illegal marriage intermediation must be strictly banned."
South Korea recently apologised to Vietnam after a newspaper ran a Seoul picture of Vietnamese women lining up for a prospective Korean husband.