The UN agency says there were more than 800 cases reported in 2017. There were less than 200 in 2012.
A number of Saudi men and women have reportedly fled the kingdom due to fear of persecution or retaliation against them for political activism.
The recent case of Saudi teenager Rahaf Mohammed al-Qunun who was granted refuge in Canada has drawn international attention.
Bessma Momani is a professor at the University of Waterloo in Canada and senior fellow at the Centre for International Governance Innovation. She joins us on Skype from the city of Waterloo to discuss this.