Denied the right to travel without consent from their male guardians and banned from driving, women in Saudi Arabia are now monitored by an electronic system that tracks any cross-border movements. Since last week, Saudi women's male guardians began receiving text messages on their phones informing them when women under their custody leave the country, even if they are travelling together.

"The authorities are using technology to monitor women," said columnist Badriya al-Bishr, who criticised the "state of slavery under which women are held" in the ultra-conservative kingdom. Women are not allowed to leave the kingdom without permission from their male guardian, who must give his consent by signing what is known as the "yellow sheet" at the airport or border.

"It would have been better for the government to busy itself with finding a solution for women subjected to domestic violence" than track their movements into and out of the country.

Saudi Arabia applies a strict interpretation of sharia, or Islamic law, and is the only country in the world where women are not allowed to drive. In June 2011, female activists launched a campaign to defy the ban, with many arrested for doing so and forced to sign a pledge they will never drive again.

The kingdom enforces strict rules governing mixing between the sexes, while women are forced to wear a veil and a black cloak, or abaya, that covers them from head to toe except for their hands and faces. The many restrictions on women have led to high rates of female unemployment, officially estimated at around 30 percent.