The human rights group was referring to an incident on 22 June, when up to 600 policemen stormed into a village in in Henan province and arrested AIDS patients and activists who had protested against the government's treatment of thousands of HIV carriers in the region.
Other villages in the area have also been raided and suspected protest leaders rounded up, rights groups and AIDS activists said.
In a statement, Amnesty urged the Chinese authorities to fully investigate the extent of HIV/AIDS transmission in Henan and other provinces due to the operation of blood-collection centres in the 1990s, and to publish the findings of the investigation.
Up to a million farmers are believed to have contracted the HIV virus after selling blood at unsanitary government-approved blood stations, leaving whole villages devastated.
The group also expressed concern at reports of indiscriminate beatings by police, and others apparently under the command of the police, during the raid on 22 June.
Authorities should clarify the names of all those detained in connection with the police raids and provide immediate guarantees for their safety, the group said.
Charges against the detainees should also be clarified, while those charged should be given access to lawyers and full medical treatment while in detention, it said.
Human Rights Watch said earlier this week that police in Henan, where many villages are devastated by AIDS, were increasingly using arbitrary arrests and violence against HIV-positive protesters seeking access to treatment.
"Persecuting HIV-positive protestors is doubly outrageous given that the state was complicit in their infection in the first place," said Joanne Csete, director of HRW's HIV/AIDS and Human Rights Programme.
Henan authorities seem to want to sweep their role in the AIDS epidemic under the rug by silencing protesters, Joanne said.
Since the government admitted the problem in 2001 after initial silence, farmers have called for access to effective treatment, care for people with HIV/AIDS, or simply a reduction in taxes. They have also decried alleged official corruption and misappropriation of state AIDS funding.