Michelle Bachelet said she "raised questions and concerns about the application of counter-terrorism and de-radicalisation measures under broad application" during her visit.
UN human rights chief Michelle Bachelet has urged Beijing to review its counter-terrorism policies to ensure they comply with international human rights standards.
Bachelet was speaking during an online press briefing on Saturday at the end of a six-day trip to China, the first by a UN Human Rights High Commissioner in 17 years.
Bachelet started her China trip on Monday in the southern city of Guangzhou before heading to Xinjiang Uighur Autonomous Region. Her office said last year it believed Uighurs in Xinjiang Uighur Autonomous Region had been unlawfully detained, mistreated and forced to work.
Bachelet reiterated, however, that her trip was not an investigation into China's human rights policies but an opportunity to engage with the government.
"I have raised questions and concerns about the application of counter-terrorism and de-radicalisation measures under broad application, particularly the impact on the rights of Uighurs and other predominantly Muslim minorities," she said.
China denies all accusations of abuse in Xinjiang Uighur Autonomous Region.
Bachelet's access was limited as China arranged for her to travel in a "closed loop", isolating people within a virtual bubble to prevent the spread of Covid-19, with no foreign press.
Rights groups and Western countries worry that China will use her trip as an endorsement of its rights record.
US State Department spokesman Ned Price said on Tuesday it was "a mistake to agree to a visit under the circumstances".
China initially denied the existence of any detention camps in Xinjiang Uighur Autonomous Region but in 2018 said it had set up "vocational training centres" necessary to curb what it said was terrorism, separatism and religious radicalism in the region.
Bachelet said she raised with the Chinese government the lack of independent judicial oversight on the operation of the centres and allegations of the use of force, ill-treatment and severe restrictions on religious practice.
In 2019, Xinjiang Uighur Autonomous Region Governor Shohrat Zakir said all trainees had "graduated".
During the media briefing, Bachelet also described as "deeply worrying" the detention in Hong Kong of activists, lawyers and journalists.