They lived in rural areas at high altitude, where temperatures in some cases are reported to have plummeted to as low as -20C (-4F).
Peruvian Health Minister Carlos Vallejos said almost 2,000 medics had been deployed in the affected areas.
He told the BBC he expected the situation to get worse before it improves.
The National Civil Defence Institute (Indeci) has launched a campaign to provide clothing and shelter to the worst affected areas.
The institute’s General Luis Salomino said he had collected 300 metric tons of clothes and other supplies from businesses, individuals and government departments in the capital, Lima.
Forecasters in Peru are predicting the cold spell will continue until September.
Even low-lying jungle regions are facing unusually cold weather, with temperatures dropping to 10C (50F).
Many adults have also died during the harsh winter, and thousands of people are suffering from pneumonia and other respiratory infections.