The Development Actions Centre (CAD) group said it had documented 572 rights violations in 2022.
Cases of torture "remain routine," the NGO's report said, citing several instances where security officers had arrested suspects and beaten them with hammers, sometimes to death.
Parliamentary elections held in July were also "the most lamentable in the country's elective history" and marked by "massive fraud," the CAD said.
President Denis Sassou Nguesso's party won the elections comfortably.
Some candidates from his Labor Party won 100-percent of the votes in their districts, according to the NGO.
Nguesso has been president of the Republic of Congo, also known as Congo-Brazzaville, for nearly 40 years.
CAD also drew attention to an affair this year in which an opposition figure from neighboring Gabon was discovered with his luggage stuffed with local currency to the equivalent of about $1.9 million.
The rights group said the scandal pointed to the "complicity of the highest authorities in the country."
The Republic of Congo ranks 164th out of 180 in the 2022 Corruption Perceptions Index by the NGO Transparency International.
Brazzaville Blasted for Rights Violations
FILE: Republic of Congo-Brazzavile president Denis Sassou N'Guesso (right) welcomed by his DRC counterpart Felix Tshisekedi in Kinshasa, DRC, Taken Sept. 14 2020.
A rights group in Republic of Congo-Brazzaville on Wednesday accused the central African nation's government of hundreds of abuses last year, running from torture to electoral fraud.
BRAZZAVILLE —