George, which has a population of about 160,000, is a picturesque coastal city located on the tourist trail along South Africa’s southern coastline.
Twenty-six people have been rescued from the debris, five of whom have died, municipal authorities said, adding that 49 others were still unaccounted for.
A construction crew of 75 people was at the site at the time of the collapse at around 2pm local time on Monday, they said.
“Three teams of rescue personnel are currently working on three different areas within the site of the collapsed building,” they said on Tuesday.
The reasons for the collapse of the building, which included an underground parking garage, are still undetermined.
President Cyril Ramaphosa offered his “deep condolences to the relatives and friends” of the victims and said his thoughts were with the families of the dead and missing.
He called for an investigation, saying it must “bring closure to the community and prevent a repeat of this disaster”.
Mario Ferreira, spokesman for the charity Gift of the Givers, which is assisting at the site, told AFP rescue workers had managed “communication with some of the people under the rubble”.
Diggers, sniffer dogs
Photos shared by the city council showed a flattened construction site with multiple rescue services present.
The building’s broken roof was still clearly visible atop the pile of rubble.
Rescue operations continued throughout Monday night with strong floodlights illuminating the cordoned-off site.
A coordination post was set up to run the operations, with numerous emergency services and about 100 personnel working in George, 400km east of Cape Town.
More diggers and sniffer dogs were dispatched from Cape Town, emergency services said.
Officials said relatives of those trapped had been asked to gather at the city hall, near the construction site, where they would be taken care of.
“Our thoughts are with the families and all those affected, who continue to wait for word of their loved ones,” Mayor Leon van Wyk said.
George is run by the Democratic Alliance, the leading opposition party, which also controls the Western Cape province.