Guangdong authorities have shut down at least seven Shenzhen non-governmental groups that advocate for the rights of migrant workers.
Veteran labour-rights activists have described the five-month crackdown as unprecedented.
Ironically, authorities have pledged that the province will be the mainland's first to ease registration requirements for NGOs from July 1.
Several activists told the South China Morning Post that they were evicted from their offices after their landlords were pressured by officials who conducted frequent checks of the facilities.
Mainland labour-rights NGOs often report of harassment from the authorities, who fear that foreign-funded and lobbying groups could organise large-scale strikes, incite protests or trigger social unrest.
Zhang Zhiru, director of the Shenzhen Spring Breeze Labour Disputes Service Centre, said he had rented the seven NGO offices that were shut down.
They include the Yuandian Worker Service Centre, the Shenzhen Migrant Worker Centre, the Green Grass Worker Service Centre, the Times Female Worker Service Centre, the Little Grass Workers' Home and another labour NGO in Longgang district that declined to be named.