The collapse happened Saturday around 2 p.m. in Makassar's warehouse area, The Jakarta Post reported.
The victims were found by fellow construction workers who were unable to rescue them before a team from the search and rescue police arrived on the scene.
"It was raining heavily with strong winds. We were trying to take shelter behind the building's walls when the building suddenly collapsed," said Muis, a worker who was at the site Saturday. He said there were 31 workers at the site at the time of the collapse.
Makassar Police chief Senior Commander Joseph Wisnu Sandjaya said the cause of the collapse has yet to be determined.
"We are still investigating whether the incident was caused by bad weather or the building itself which did not meet the construction standards," Wisnu said.