SAUDI Arabia has detained women's rights activists for working with "foreign entities" only weeks before its ban on women driving is lifted.

The kingdom's state security said it had detained seven people and rights activists say all of them had worked in some capacity on women's rights issues, with five among the most prominent and outspoken women's rights campaigners in the country.

Pro-government media outlets have splashed their photos online and in newspapers, accusing them of betrayal and of being traitors.

Saudi Arabia's 32-year-old heir to the throne, Crown Prince Mohammed bin Salman, has previously positioned himself as the force behind the kingdom's reforms, but Human Rights Watch said his reform campaign "has been a frenzy of fear for genuine Saudi reformers who dare to advocate publicly for human rights or women's empowerment".

"The message is clear that anyone expressing scepticism about the crown prince's rights agenda faces time in jail," said Sarah Leah Whitson, Middle East director at Human Rights Watch.

The women activists had persistently called for the right to drive, but stressed that this was only the first step toward full rights.

For years, they also called for an end to less visible forms of discrimination, such as lifting guardianship laws that give male relatives the final say on whether a woman can travel abroad, obtain a passport or marry.

The Interior Ministry did not name those arrested, but said the group is being investigated for communicating with "foreign entities," working to recruit people in sensitive government positions and providing money to foreign circles with the aim of destabilising and harming the kingdom.