The New York-based organization Human Rights in China says police this week detained more than 200 out-of-towners in raids on two hostels and a squatter village, and then forced most of them to return to their hometowns.
The detentions of these "petitioners" come just days before the 56th anniversary of the founding of the People's Republic of China - a busy national holiday.
Human rights activists say such petitioner round-ups often occur around politically sensitive anniversaries and before holidays.
Hou Wenzhuo is Director of the Empowerment and Rights Institute, a Beijing human rights activist organization. She says the government feels threatened by rising incidents of unrest combined with better-organized activists and petitioners.
"They're [the government] very paranoid," said Hou Wenzhuo. "And, there is a reason to be paranoid. During the national holidays, they think that people may use various memorial days to do something big."
Incidents of unrest and the number of petitioners coming to Beijing have increased rapidly in recent years, along with a widening wealth gap, corruption, and perceptions of injustice.
The Chinese government says there were 74,000 riots and demonstrations in China last year, up from 58,000 in 2003, and many of those were protests by people who felt local officials had treated them unjustly.
Beijing has expressed concern about social stability, and has made efforts to address the complaints. Earlier this year, the government revised rules on petitioning to try to make local authorities more accountable.
Still, the Beijing police, and police from the provinces, routinely round up petitioners and send them back home.
Public Security officials had no comment on the alleged detentions. However, China's state media reported security had been stepped-up for the national holiday.
The statement issued by Human Rights in China this week said that despite recent efforts by China's national government to improve the petitioning process, this week's detentions suggest that control of society remains the government's priority.