The top Communist Party boss in China's Xinjiang region said in an article published Wednesday that the restive mainly Muslim province faces a period of "intense struggle" against separatism.

The lengthy article in the party mouthpiece People's Daily comes as China is in the midst of a crackdown against what it says is religious-inspired extremism in the nominally autonomous and resource-rich region, home to the mostly Muslim Uighur and other ethnic groups.

"Xinjiang is in an active period of violent terrorist activity," wrote Zhang Chunxian, Xinjiang's party secretary, adding that the region faces an "intense struggle against separatism".

"Only by resolutely relying on law to govern Xinjiang" can the region's ethnic groups be united and won over while isolating and cracking down on enemies, he added, stressing that China's legal system must be used, independent of Western models.

Zhang was appointed as regional party secretary in 2010 after his predecessor was sacked in a move widely seen as a bid to allay public anger following riots between Uighurs and China's ethnic majority Han that left about 200 people dead the previous year.

Violence linked to Xinjiang has intensified since early 2013 amid a series of bloody clashes and attacks in the region and beyond it.

Beijing, which blames Xinjiang-related violence on "religious extremists", "separatists" and "terrorists", has responded by launching a crackdown, with hundreds of arrests and around 50 death sentences or executions announced since June.

"Xinjiang is a multicultural region of many ethnicities and religions with numerous interwoven problems that are complex and sensitive," wrote Zhang, who is Han Chinese.

He did not specify any particular belief or group, in keeping with the conventions of official media in China, which emphasise harmony in the country's ethnic and religious makeup.

Party leaders have promised to strengthen the rule of law "with Chinese characteristics", though experts caution the concept refers to greater central control over the courts, rather than judicial independence.

Zhang conceded as much.

"The fundamental point (of Chinese rule of law) is the insistence on the integration of the party's leadership, the people being the master of their own affairs and governing the country by the rule of law."

China's rule of law "isn't that of 'separation of powers' and we can't go the way of the West's 'judicial independence' and 'judicial neutrality'," he wrote.