Residents in China's northwestern Xinjiang region have complained on social media about what they say are harsh coronavirus lockdown measures in the sensitive region after a local outbreak.

China -- where the disease first emerged -- had largely brought domestic transmission under control through lockdowns, travel restrictions and testing, but sporadic regional outbreaks have emerged.

A new cluster in Xinjiang's capital Urumqi in mid-July prompted fresh restrictions, with 902 cases officially reported.

Officials said this month they had "effectively contained" the spread of the Urumqi cluster, and there have been no new cases reported in the past eight days. But hundreds of local residents have gone on to local social media forums in recent days to complain about harsh conditions.

With some of the comments removed -- China's internet is heavily censored -- users tried to also voice their complaints on local forums on the Twitter-like Weibo platform in Beijing, Shanghai and Guangzhou.

Social media users shared photos of front doors sealed with steel crowbars, and locks installed by community workers.

"Why can't prefectures with no cases remove the lockdown? Why do you need to lock down the whole of Xinjiang?" read one comment on Weibo, which received thousands of likes. "Doors have been sealed, this has brought huge inconvenience to workers and people's lives. Prices of daily items have risen... many things I buy are expired."

Some residents also wrote that they were forced by authorities to take Chinese medicine daily, and were required to film themselves doing so.

One video from Saturday showed dozens of high-rise residents in Urumqi yelling from their windows in despair.

Stranded migrant workers, university students, business travellers and tourists also complained about not being able to leave Xinjiang. "I have even taken three nucleic acid tests... but community workers won't let me leave," one user wrote on a message board run by the state-run People's Daily.

Urumqi authorities said Monday that lockdowns would be eased in areas that had no virus cases, according to a report in the state-run tabloid Global Times.

Around half of Xinjiang's more than 21 million people are ethnic Uighurs and other Turkic Muslims, many of whom complain of decades of political and religious oppression by China's ruling Communist Party, which the government denies.

Activists have accused the Chinese government of incarcerating about one million Uighurs and other Turkic people in Xinjiang camps. Beijing has described them as vocational training centres to counter Islamic radicalism.