The letter would give the purpose of the trip, The New Straits Times reported.

Foreign Minister Datuk Seri Rais Yatim said the aim is to protect women who might be vulnerable to recruitment as drug mules. The newspaper said 119 Malaysians, mostly women in their 20s, are imprisoned in Asia, Europe and South America, for drug crimes.

Rais said many of the women working as drug couriers claim to be traveling for study or to attend conferences.

"With this declaration, we will know for sure where and for what she is traveling overseas," he said.

But women's groups reacted angrily to the plan.

Faridah Khalid of the National Council of Women's Organizations Malaysia called it "an infringement on our rights."

"We're the victims and now you're creating more problems," she said. "Why must you put more restrictions on women?"

Drug trafficking groups have turned to Malaysia for couriers because citizens can travel widely without visas.