Saudi Arabia's historic lifting of a ban on women driving will be a litmus test for its king-in-waiting, who has sought to sideline the kingdom's arch-conservatives as he accelerates reforms, analysts say.

The kingdom will issue driving licences to women from next June, in the most striking reform yet credited to Crown Prince Mohammed bin Salman, despite the risk of a backlash from hardliners

But after his recent crackdown on dissenters, including prominent clerics with huge followings, experts say the prince may face only a muted opposition.

"The lifting of a ban [...] will likely serve as a litmus test for Crown Prince Mohammed bin Salman's ability to introduce economic and social reforms despite conservative opposition," said James Dorsey, a fellow at Singapore's S. Rajaratnam School of International Studies.

"If last week's national day celebrations in which women were allowed to enter stadiums in anything to go by, the opposition is likely to be limited to protests on social media."

On Saturday, women were allowed for the first time into a sports stadium to mark national day, a move that chimes with the Prince Mohammed's 'Vision 2030' reform plan.

Men and women also danced in the streets to drums and thumping electronic music, in scenes that were a stunning anomaly in a country known for its tight gender segregation and austere vision of Islam.

This gambit to loosen social restrictions in the ultra-conservative society was made possible partly by the latest crackdown, which was seen as a show of force by Prince Mohammed, experts say.

Jamal Khashoggi, a prominent Saudi journalist and former government adviser who went into exile in the United States, described a new Saudi era of "fear, intimidation, arrests and public shaming" in an article published in The Washington Post.

'Assertion of power'

Those arrests were not directly related to the driving ban, but apparently to an ongoing crisis with Gulf rival Qatar, said Jane Kinninmont from London-based Chatham House.

"But the arrests represented an assertion of power over the independent, politically influential clerics and sent a message that Prince Mohammed does not see himself as beholden to them as partners in government," Kinninmont told AFP.

"The fact that they have been arrested without significant unrest being triggered is likely to have made the Saudi leadership more confident that it can make (social) change without much in the way of opposition."

Prince Mohammed is set to be the first millennial to occupy the throne, in a country where half the population is under 25, when he takes over from his 81-year-old father King Salman.

"I think Prince Mohammed is ideologically committed to taking the Saudi state in a new direction: less austere, more nationalist," said Kristin Diwan, from the Arab Gulf States Institute in Washington.

Unlike previous rulers, he has shown a willingness to tackle entrenched Saudi taboos, and is seen as catering to the aspirations of youth with an array of entertainment options and promoting more women in the workforce.

"Women should obviously have had the right to drive a long time ago -– the fact that this decision was so long in coming shows just how much has changed in Saudi Arabia with Prince Mohammed now wielding executive authority," said Perry Cammack, a fellow at the Carnegie Endowment for International Peace.

'Discriminatory practices'

But hardliners could still emerge as a potent threat.

Many Saudis on social media, irked by the mixing of genders on national day, derisively compared the country to "Las Vegas".

"Patriotism does not mean sin" became a widely used hashtag, while some called for the religious police, whose powers have been curtailed in recent years, to restore moral order.

The government has sought to downplay their influence, saying that most senior clerics in the kingdom "agree that Islam does not ban women from driving".

But aside from religious hardliners, women also face opposition from a conservative society that is unaccustomed — or fundamentally opposed — to women drivers.

Under the country's guardianship system, a male family member — normally the father, husband or brother — must grant permission for a woman's study, travel and other activities.

It was unclear whether women would require their guardian's permission to apply for a driving licence.

"If by June next year women in Saudi Arabia are driving the streets without fear of arrest, then this will be a cause for celebration," said Philip Luther, from Amnesty International.

"But it is just one step. We also need to see a whole range of discriminatory laws and practices swept away."