A warning notice on the country’s customs administration website listed 81 items imported by companies including Nike, H&M and Zara.
In March, China targeted foreign clothes retailers as an international backlash grows over claims of abuses in the cotton-growing Xinjiang region.
Earlier this year, several Western nations imposed sanctions on China.
The announcement from China’s General Administration of Customs included items like children’s clothing, shoes, toys, toothbrushes and baby bottles that were spotted during examinations from June 2020 to May 2021.
Nine batches of H&M girls’ cotton dresses were said to contain “dyes or harmful substances [that] may be absorbed by the body through the skin, mouth, etc. and endanger health.”
The same issue was raised for children’s clothes imported by Zara, Nike boys’ t-shirts and batches of Gap boys’ cotton pyjamas.
H&M, Zara, Nike and Gap have not yet responded to requests for comment from the BBC.
The notice is the latest blow to Western clothing brands operating in China, which have been targeted amid an international backlash over claims of abuses in the cotton-growing Xinjiang region, home to the mostly Muslim Uighur minority group
Some firms’ online shops have been blocked and their stores have vanished from some digital maps.
China initially targeted H&M and Nike but that has widened to include Burberry, Adidas and Converse, among others.
In March, several Western countries imposed sanctions on officials in China over rights abuses against the mostly Muslim Uighur minority group.
China has detained Uighurs at camps in the north-west region of Xinjiang, where allegations of torture, forced labour and sexual abuse have emerged.
The sanctions were introduced as a coordinated effort by the European Union, UK, US and Canada.
Beijing has denied the allegations of abuse, saying the camps are “re-education” facilities used to combat terrorism.
China has also hit back with retaliatory sanctions on Western lawmakers, scholars and institutions.