The search is expected to continue on Tuesday morning for the people who are believed to be buried under the rubble after a house that was being renovated collapsed in Alberton, south of Johannesburg.
The death toll has been revised to seven and several others injured.
The Labour Department has vowed to take strong action against those responsible for the accident.
The construction workers died after a concrete slab fell on them in the house they were renovating. Thirteen people have been critically injured, five with serious injuries but in a stable condition and one with minor injury.
The workers involved are contracted by an independent construction company, and the families of the deceased have not yet been informed.
On Monday, its team of inspectors visited the accident scene in an effort to establish its cause.
Emergency services personnel worked throughout the night to ensure that everyone is accounted for following the collapse. They have not ruled out the possibility of finding more bodies under the rubble.