Six fire engines were sent to tackle a fire on the 12th floor of Albert Barnes House on New Kent Road on Friday afternoon.
The London Fire Brigade says that a quarter of a flat on the 12th floor was damaged in the blaze.
A brigade spokeswoman said that a woman left the flat before firefighters arrived at the scene.
Friday evening rush hour traffic around Elephant & Castle was delayed by the closure of one lane of New Kent Road. Traffic was directed by a policeman.
Three years ago a larger fire caused more substantial damage to the block.