The New York-based organisation, Human Rights Watch, says international companies operating in a special industrial zone in Mexico are forcing female workers to take pregnancy tests as a condition of employment.

A Human Rights Watch report says women who work in the maquiladora zone, along the US border, are also obliged to provide details of their contraceptive use and sexual activity.

The organisation is calling on the Mexican government to implement legislation outlawing such practices.

And the group is urging thecompanies involved to end sex discrimination it says they would never dare defend in their home countries, such as the US and Germany.