BEIJING -- The capital of China's restive western region of Xinjiang has introduced a law banning veiled robes in public amid measures taken by Beijing to curb Muslim extremism, authorities announced Thursday.

The law in the predominantly Muslim region comes as Beijing intensifies a campaign against religious extremism that it blames for the violence that has left hundreds dead in the past 20 months.

"This fits into the larger pattern, keeping up with the trend in the past five years that has really intensified in the last year by the government to try to forcibly reshape and standardize the type of garment among the Uighur females," said James Leibold, a scholar of ethnic policies at Australia's La Trobe University.

Xinjiang is home to the Turkic-speaking Uighur minority Muslims, who have complained of China's repressive rule and economic disenfranchisement under a government dominated by the majority Han Chinese.

In clamping down on violence in Xinjiang, authorities are targeting what they call manifestations of religious extremism among Uighurs, such as beards and women's veils. Scholars say they are not necessarily expressions of extremism but cultural choices by Uighurs, and they warn the heavy-handed measures may anger ordinary Uighurs.

"It polarizes the tensions even further, and you get violent push-back," Leibold said, noting that acts of unveiling Uighur women have been met with resistance in Xinjiang.

In August, the northern Xinjiang city of Karamay announced that young men with beards and women in burqas or hijabs would not be allowed on public buses.

In another public campaign called "Project Beauty," authorities have banned veils and masks that cover up a woman's face. Uighur women also are requested to tie headscarves behind their ears, instead of wrapping them around their chins, a custom authorities say is not indigenous to Uighur cultures.

Police also have raided women's dress shops in Xinjiang and confiscated full-length robes.

The new law was passed by the Urumqi legislature's standing committee on Wednesday but needs endorsement at the regional level before going into effect.

Muslims make up about 1.8 per cent of the Chinese population. In Xinjiang, non-Muslim ethnic Han Chinese account for 41 per cent of the region's population.