An outspoken billionaire Saudi prince has called for an "urgent" end to his country's ban on women driving.

"Stop the debate: Time for women to drive," Prince Alwaleed bin Talal said on his official Twitter account, @Alwaleed_Talal.

Alwaleed is an unusually outspoken member of the Saudi royal family who holds no political posts but chairs Kingdom Holding Co, interests of which include US banking giant Citigroup and the Euro Disney theme park.

Philanthropist Alwaleed is a longtime advocate of women's rights in the kingdom, which has some of the world's tightest restrictions on women and is the only country where they are not allowed to drive.

In conjunction with his short tweet, Alwaleed's office issued statement Tuesday outlining his reasons for supporting an end to the ban.

"Preventing a woman from driving a car is today an issue of rights similar to the one that forbade her from receiving an education or having an independent identity," Alwaleed said in the statement.

"They are all unjust acts by a traditional society, far more restrictive than what is lawfully allowed by the precepts of religion."

He also detailed the "economic costs" caused by women having to rely on "foreign" private drivers or taxis. Even if their husbands can take time out to transport them, that requires temporarily leaving the office and "undermines the productivity of the workforce," he said.

"Having women drive has become an urgent social demand predicated upon current economic circumstances."

Saudi Arabia's oil revenues fell by 51 percent last year following a collapse in global prices, which remain at less than half the level they were two years ago.

As a result, the government has delayed major projects, cut spending, and raised prices for everyday services including water and electricity.

The kingdom in April announced its Vision 2030 plan to diversify its oil-dependent economy and employ more Saudis, including women.

Unveiling that plan, Deputy Crown Prince Mohammed bin Salman, 31, said social change cannot be forced.

On women driving, he said: "So far the society is not persuaded... but we stress that it is up to Saudi society."