The building in which three firefighters died on Wednesday was only 21% compliant with safety regulations.
This is according to Gauteng MEC for infrastructure development Jacob Mamabolo.
Two firefighters died after they became trapped in the building that is shared by the departments of health, human settlements and cooperative governance. Another firefighter fell to his death earlier in the day while battling the blaze.
"The building simply does not comply with safety and health regulations. Government officials will stay at home until there is a safe building to relocate them to," Mamabolo said at a media briefing at the scene on Wednesday afternoon.
All government officials were safely evacuated after the fire broke out on the 23rd floor. However, 13 employees, as well as eight firefighters were taken to hospital to be treated for smoke inhalation.
Investigations into what caused the blaze would be undertaken, although there have been suspicions that an electrical fault could be to blame.
Allegations of multiple fires
"At this point, we are not aware of what the causes of the fire are. The City of Johannesburg, working together with us, will conduct an investigation and I would like to appeal to everybody to not speculate," Mamabolo said.
The National Education and Health Allied Workers' Union (Nehawu) told News24 that several shop stewards were dismissed after they raised concerns about the building in 2014.
"As a union we have been consistently raising concerns about the defects in the building since 2014," Nehawu Gauteng provincial secretary Tshepo Mokheranyana said.
Some of the staff alleged that this was the third fire in a year.
Mamabolo declined to comment on the claims.
"I will engage with the union and commission an inquiry, and I will make sure we get a proper report on that," Mamabolo told News24.
Johannesburg emergency services' Nana Radebe said the fire had been put out by late Wednesday afternoon.
The City of Johannesburg has passed on its sincerest condolences to the families of the deceased.
MMC for Public Safety Michael Sun said both Albertina Sisulu and Pixley Seme streets would be closed on Thursday to ensure that no pedestrians or motorists came near the building as glass was still falling.
"We certainly don't want to see anymore injuries," Sun said.