A bombshell leak of internal Chinese Communist Party documents has exposed in unprecedented detail China's crackdown against Muslim minority groups, revealing President Xi Jinping's decree for "no mercy".

Foreign Minister Marise Payne labelled the revelations of China's brutal and secretive campaign in its western Xinjiang province "disturbing" and promised to continue raising Australia's concerns about Beijing's human rights record.

Security personnel on patrol outside a mosque attended by Uighurs in Xinjiang. Credit:AP

The 400 pages of documents leaked to The New York Times expose the thinking behind the crackdown, including Xi's call for an all-out struggle using "organs of dictatorship", "a period of painful, interventionary treatment" and showing "absolutely no mercy". The CCP's top official in the province commanded a "smashing, obliterating offensive" and urged colleagues to "round up everyone who should be rounded up".

Included in the trove of documents is a directive on how to handle students returning home to Xinjiang to find their relatives detained. Officials were advised to tell students their relatives were receiving "treatment" for exposure to the "virus" of extremist Islam that had "infected" them, while acknowledging they had not committed any crimes. Students were to be warned their behaviour could affect their relatives' time in detention.