Most of those on board were travelling home from a religious festival in the Andean district of Santa Teresa, according to a local fire chief.
Investigators say there were no survivors from Friday night's accident.
People often travel by lorry in the Peruvian Andes because of a shortage of public transport.
The mayor of the Santa Teresa district, Ruben Pinto, said the search operation was continuing but that children were among the victims.
"The vehicle remains trapped in a gorge of the River Yanatile, there are no survivors," chief investigator Juan Carlos Valverde told Peruvian radio.
"At the moment we are carrying out the identification, registration and handing over of bodies to the families who are here."
"Regrettably, those who have lost their lives are peasant farmers like us," Mr Pinto said. "The town of Santa Teresa is not prepared for an accident of this scale."
At least 52 people were killed when a lorry plunged 200m (650ft) off a road into a gorge in the Cusco region of south-eastern Peru, officials say.