The Sojpal Building opposite the City Market collapsed on one side at around 9am on Tuesday morning.
Central Police boss Patrick Oduma says no one was injured during the incident.
Speaking to Capital FM News, Starehe area Deputy Commissioner Omar Beja urged members of the public to avoid the area.
Other than the building being old, Beja said the collapse could have been caused by dip excavation to pave way for an upcoming building besides it.
“We are waiting for the experts to unveil the cause though besides the building there is a very dip foundation of another building which could have weakened its foundation,” he said.
“The building is very old, it was built in 1935.”
Members of the public have been warned against any attempts of looting saying it’s dangerous as the rest of the building may also collapse.
“People should avoid this area. The remaining section of the building may collapse also while trying to loot and they end up being injured there,” he warned.