The report released Tuesday is titled "Shut up if you don't want to be killed." It documents alleged human rights violations and calls for the department to thoroughly investigate them.
Amnesty says the government reported at least 154 people killed by police from January to July of this year, compared with 125 people in the same period last year.
The group says police describe the majority of killings as occurring during an exchange of gunfire, but that forensic tests show otherwise.
Dominican officials did not return calls for comment.