In a report presented in Mexico City, the group said it had found evidence of extrajudicial executions, arbitrary detentions and deaths and injuries due to excessive use of force by Maduro's government.
The Venezuelan government did not immediately respond to a request for comment.
Venezuela is reeling from an acute political and economic crisis that has worsened since January when opposition leader Juan Guaido declared himself interim president, arguing that Maduro's reelection was fraught with irregularities.
Guaido, who has been recognized as Venezuela's rightful leader by about 50 countries including the United States and much of Latin America, has sought Maduro's resignation.
"As we have said for years, in Venezuela there is a systematic policy of repression against the opposition," Erika Guevara, Amnesty International's director for the Americas, told reporters after the presentation.
As Venezuela was rocked by protests demanding a change of government in January, at least 47 people were killed, according to the report. More than 900 people were arbitrarily detained over the five days of protests in late January, including 770 detentions in just one day.
An Amnesty International team visited Venezuela between Jan. 31 and Feb. 17 and documented six extrajudicial executions, three cases of excessive force and six arbitrary detentions, according to the report.
The cases "are representative of a broader pattern of possible human rights violations that took place in January 2019," the report states.
The six extrajudicial executions bore many similarities, the group wrote. All of the victims were young men who were shot in the chest while in custody, and some were tortured.
"In all six cases, the crime scene was tampered with in order to cover up the facts, as were the bodies of the victims," Amnesty International wrote.
The group's investigators also found that families of the victims received minimal information about government investigations into the acts of violence.
"In January 2019, multiple acts of violence were committed consistently in all states and with a high degree of coordination between the security forces at the national and state levels," Amnesty International wrote in the report."The authorities right up to the highest level, including Nicolas Maduro, have at the very least tolerated such attacks."