Rescue efforts were halted overnight at the rugged site of Tuesday's crash.
"There are still a lot of bodies to recover," district attorney Cesar Arroyo said late on Monday. He said between 37 and 40 bodies had been found.
"We've halted rescue efforts because its dark, muddy and difficult at the crash site," he added. "We'll finish the rescue tomorrow."
"Among the survivors are 50 passengers and two crew members," state-run Tans Peru airline company's spokesman Jorge Belevan said, while allowing that others may still be alive.
"These people have been contacted and all of them are alive," Belevan said, adding that he did not rule out discovering more survivors among the 92 passengers and eight crew members aboard Tans flight 204 from Lima.
He said among the 16 foreigners on the flight, five Americans who belong to a single family and two Italians had survived. He had no information on the others.
Survivors include 50 passengers
and two crew members
Flight 204 listed 11 Americans, two Italians, an Australian, a Spaniard and a Colombian. All the other passengers and crew were Peruvian.
Peru's President Alejandro Toledo earlier said between 70 and 80 people have been killed.
"There were between 20 and 30 survivors" on the jet which was on a flight between the capital Lima and Pucallpa, Toledo said.
"Until now, there are 40 cadavers that rescue teams are pulling from the wreckage. There could be more deaths, we assume some 60 people in total, since we've rescued 20 injured people," a police officer in the town of Pucallpa told RPP radio.
The crash - the fifth this month involving a passenger plane -
comes a week after a chartered Colombian jetliner crashed in
Venezuela, killing all 160 on board.
A Colombian plane crashed last
week killing all 160 on board
A Cypriot Boeing 737 crashed on 14 August near Athens, killing all 121 people on board; a Tunisian-chartered ATR-42 dived into the sea off Sicily on 6 August, killing 16 people; and an Air France Airbus A340 crashed on landing in Toronto on 2 August. All 309 passengers and crew survived.
A spokesman for the Tans said the plane made an emergency landing without its landing gear in the jungle town of Pucallpa, 785km northeast of Lima.
"We are standing next to the cabin and we can see the body and it appears that it is a flight attendant in her uniform. We can also see a person, it appears to be a female," a correspondent for Radioprogramas radio said.
"There are bodies of children. Many bodies."
Radio reports of an accident started coming in after 4pm (2100 GMT), saying a plane had crashed about 9km from the municipal airport near the jungle city Pucallpa.
A man identifying himself as William Zea, a passenger on the plane, told CPN radio by telephone that the plane was travelling from Lima to Pucallpa, and from there on to the northern jungle city of Iquitos when "the plane suffered some malfunction and we went down".
Tomas Ruiz, another passenger, told Radioprogramas: "It seems it was a matter of the weather. Ten minutes before we were to land in Pucallpa, the plane began to shake a lot."