At least three people were killed in the protests, while 30 others were injured.
The report said that "in almost all cases of human rights violations" there had been no investigation or disciplinary action, "nor has any police officer been prosecuted", the report said.
Kagari said it was vital that any officer suspected of involvement in human rights violations be held to account.
"They must be held responsible for their actions if policing is ever going to change for the better in Mozambique," she said.
But the report also noted that Mozambican police faced "numerous challenges stemming from high crime rates, a backlog of criminal cases in the judicial system, and occasional violence against police by criminal elements".
It said that these had led to the police dealing with suspects and criminals violently and at times killing suspects.
The report also criticised the authorities for not providing more information to the public.
"The police have generally been unresponsive to the public, providing very little information to those who have lodged complaints against the police for human rights-violations.
Victims virtually never receive compensation for these violations," the report said.
Amnesty's report comes one day after Alice Mabota, president of Mozambique's leading human rights organisation, Liga dos Direitos Humano (the League for Human Rights), said in Maputo that the human-rights situation in Mozambique had deteriorated in the past few months.
Mozambique's police refused to comment on the report.