According to express.co.uk, the accident occurred on a curve of the highway bordered by a huge, mountainous slope leading down to a river.
Emergency personnel, who were present at the site, said that the bodies of the victims which were swept away in the river located below the cliff were recovered.
Police officials have confirmed that 44 people have been killed.
President Pedro Pablo Kuczynski wrote on Twitter: "My condolences to the relatives of the victims of the transit accident in Arequipa. We have taken all steps to provide immediate rescue support and transfer victims to the closest health centers so they can be attended immediately."