The gang had sent 18 women from Vietnam's poor southern Mekong delta region to Malaysia over the past three years before the ring leaders were arrested in January, said a Can Tho court official who declined to be named.

Hua Thi Thuy Trang, 35 - identified in media reports as a former prostitute who had worked in Cambodia, Malaysia and Singapore - was jailed for 17 years, while her four accomplices received terms of five to 12 years, the official said.

The Thanh Nien daily reported that the gang lured the women to Malaysia with promises of waitressing jobs, paying their families 800 dollar each while forcing the women to sign promises to pay the group 4,400 dollars each.

Once in Malaysia, the women were closely guarded during the day and forced to have sex with about seven men per night each without payment, the report said, adding that while those who resisted were beaten and starved.

Thousands of Vietnamese women are believed to be trafficked every year, especially to neighbouring China and Cambodia, lured with promises of jobs but then forced to work as prostitutes or to marry.

Between 2005-07, Vietnamese police say they detected 900 trafficking cases involving 2,200 victims, state media have said.

The true extent of the trafficking is unknown and police suspect many of the more than 20,000 Vietnamese women and children who have gone missing since 1975 were victims of trafficking.

Agence France Presse - December 30, 2008