Residents of the Setswetla informal settlement in Alexandra are at risk of being swept away as heavy rains are expected to continue until tomorrow.
The residents, who have lived in the area for the past 17 years, have their shacks hanging precariously on the banks of the Jukskei River, which always washes away such structures during heavy downpours.
The residents have continued to live there despite warnings to move.
Councillor William Shuene said yesterday that some people had previously been removed from the area.
"We have removed people but others come and erect shacks on the same spot," Shuene said.
He said the process to solidify the river banks after moving inhabitants was continuing.
Lestinah Mashakene, who lives with eight family members in a two-room shack on the edge of a donga next to the river, said they had nowhere else to go if disaster were to strike.
The area does not have water and electricity.
The rain warning affects the whole country after a SA Weather Service prediction that heavy rains would continue until tomorrow.
In anticipation of the possible disaster, the Johannesburg Emergency Services said it has devised a plan to assist those who will be affected.