A prominent Chinese anti-discrimination organisation said Monday that police have arrested two of its staff, as the ruling Communist Party seeks greater control over independent rights campaigners.

Beijing-based charity Yirenping has campaigned for equal rights for people with diseases including Hepatitis B and HIV/AIDS and provided them with legal training and advice.

Police in the southern province of Guangdong "arrested" group members Guo Bin and Yang Zhanqing on Friday on charges of running an illegal business, Yirenping said on a social media account.

The ruling party has in recent months stepped up its scrutiny of non-governmental organisations (NGOs), amid state media warnings of "hostile foreign forces" said to be using them to foment revolution.

The government is also mounting a wider crackdown on activists, lawyers and journalists critical of the party, which has seen hundreds detained and dozens jailed.

Yirenping reportedly came under increased pressure after it called for the release of five feminist campaigners detained in March. Its offices were raided shortly afterwards.

The five women were released on bail around a month later after an international outcry, but China's foreign ministry declared Yirenping was suspected of a crime and "would be punished".

Guo and Yang's work at Yirenping was concerned with lobbying on behalf of Hepatitis B carriers, the group added in its social media post.

"These public-spirited people should be rewarded by the government and not locked up on trumped-up charges," it said.

Police in Guangdong were not immediately available for comment. The foreign ministry said Monday it had not heard of the case.

Maya Wang, a researcher for US-based group Human Rights Watch, said she was "deeply worried" by the detentions.

"The government's ongoing campaign against this key NGO signifies the government's strengthened resolve to control civil society and to crack down on dissenting voices," she added.

The government is considering putting police in charge of supervising all activities by foreign NGOs working in the country.