The government is cracking down on women from Southeast Asia and China who make sham marriages with elderly Malaysians in order to work here, often as hostesses in karaoke bars.

The New Straits Times said women from Vietnam, Thailand, Indonesia and China were involved in the scam, in which Malaysian agents pay local men to enter into the marriages.

Deputy Home Affairs Minister Tan Chai Ho said that the discovery of 10 young foreign women in karaoke joints in Penang state, who secured work visas after marrying much older men, was the tip of the iceberg.

"We are tracking them down. But it is difficult to prove that these marriages are scams," he told the daily.

Tan said immigration officials were investigating other cases of "spouse visa" abuse, but that even when raids were carried out on entertainment venues they could not always prove the women were working illegally.

"They claimed to be married to locals and said they were at the places of entertainment looking for a friend," he said.

"The very fact that they carry their marriage certificates to such places indicates that they are involved in something suspicious," he added.

"Their husbands, when contacted, said they allowed their wives to go to such places."