DUBAI - A Saudi cleric who said women should not drive because their brains shrink to a quarter the size of a man's when they go shopping has been banned from preaching, state television said.

Saad al-Hijri was suspended from all religious activity after advising against allowing women to drive in a speech that contained comments "diminishing human value", the broadcaster quoted a spokesman for the governor of Asir province as saying.

Ultra-conservative Saudi Arabia is the only country in the world that bans women from driving, despite ambitious government targets to increase their public role, especially in the workforce.

Women in the kingdom are also bound by law to wear long robes and a headscarf and require the consent of a male guardian for most legal actions.

In a video identifying him as the head of the religious edicts department in the southern province, Hijri asked what the traffic department would do it if it discovered a man with only half a brain.

"Would it give him a license or not It would not. So how can it give it to a woman when she has only half" he said.

"If she goes to the market she loses another half. What is left A quarter...We demand the traffic department check because she is not suitable to drive and she has only a quarter."

The comments sparked anger on social media, which is hugely popular in the kingdom. Twitter users shared the video, many criticising it and making jokes about his remarks, under the Arabic hashtag "Al-Hijri_women_quarter_brain"

Some users posted pictures of Saudi female scientists and academics in response and questioned Hijri's own intellectual capacities.

His suspension, ordered by the provincial governor, was aimed at preventing the spread of views that spark controversy and do not serve the national interest, the provincial spokesman said, according to Ekhbariya TV's official Twitter account.

Any others who used religious platforms to preach such views would also be banned.

The government's modernising reforms, backed by Saudi Arabia's business class, have sparked tensions with influential clerics upon whose support the ruling family relies. Some clerics have millions of followers on social media.

(Reporting by Sylvia Westall and Ahmed Tolba; editing by John Stonestreet) ((sylvia.westall@thomsonreuters.com; Dubai Newsroom +971 56 216 6204; Reuters Messaging: sylvia.westall.thomsonreuters.com@reuters.net))