"We will continue with rescue services and probably we'll find a body or two. There are still families looking for their relatives," Eugenio Laborinho, the national commander of the Civil Protection Service, said.
About 180 people were believed to be in the seven-storey building when it collapsed, some 145 of them detainees being held while under investigation, Roberto Leal Monteiro, the Interior Minister, said.
Sniffer dogs had been picking through the rubble while rescue teams used their hands with cranes assisting by lifting concrete to find survivors.
Roberto Leal Monteiro, the interior minister, has called on Portuguese Engineering Laboratories to investigate the causes of the collapse of the building, erected in 1974 during the colonial era.
Past warnings from top officials of the National Criminal Investigation Department (NCID) over the deteriorating state of the seven-storey building went unheeded, Radio Ecclesia reported.
While the authorities have refused to comment on the cause of the disaster, the radio said that a seventh floor had been added to the original building, with a massive generator placed on the top floor.
A total of 102 of those injured were treated in hospital. Nine were in a serious condition.
The authorities have not commented on the cause of the incident.
Angola's infrastructure has been badly damaged by a civil war that has lasted nearly 30 years.