Jorge Molina, rescue operations chief for area firefighters in Peru, said: "The possibility of finding someone alive is nearly nil."
About 400 firefighters, including groups from Britain, Spain and neighbouring South American nations, have taken part in the search and rescue efforts.
Emergency workers rescued only two survivors but pulled 148 bodies from the ruins of the San Clemente church in Pisco, which collapsed when the tremor hit during a funeral, Molina said.
More than 500 people were killed in several towns in the central coast area, most of them crushed when their flimsy mud-brick homes collapsed.
Disease
 |
Hundreds of thousands of people
have been made homeless [AFP] |
Carlos Vallejos, Peru's health minister, said about 1,500 doctors and nurses were struggling to prevent the spread of epidemic diseases among earthquake victims.
"The problem is not only that there are still unfound bodies, the problem is water" he said.
Medical officials said Saturday that symptoms of respiratory infections have begun to emerge as a floating dust cloaks the town and warned the situation could deteriorate into an epidemic if residents fail to take precautions.
A field hospital has been set by 22 US doctors in the grounds of the Pisco football stadium.
Teresa Bo, Al Jazeera's correspondent in Pisco, said aid was reaching some neighbourhoods, but that many survivors were still not receiving any help.
"Here in Pisco there are about a dozen tents that are hosting people who have lost their homes. There is an ambulance and there are soldiers here to protect the humanitarian aid that is arriving," she said.
"But some areas that we have visited before are not seeing any kind of aid. People are saying they have no water or food."
Looting
Meanwhile, as reports of looting in the aftermath of the earthquake persisted, Alan Garcia, Peru's president, ordered more soldiers to Pisco and promised that authorities would keep the peace "whatever the cost".
Reports said that more than 1,000 troops and police armed with assault rifles were sent to patrol the streets of Pisco.
Desperate mobs have been looting trucks carrying food and water.
Some people tried to break into the air force base near Pisco where relief efforts have been centralised and close to the provincial capital of Ica, there were reports a mob tried to raid a convoy of trucks carrying emergency supplies.
Spanish firefighters, searching the rubble of a Pisco church, had to stop their work late Saturday when gunfire broke out around them, although it remained unclear where it was coming from.
Garcia has promised to rebuild Pisco, which lost 85 per cent of its houses after what was the most devastating earthquake to hit the country since 1970.