KwaZulu-Natal police could on Thursday not confirm a Daily Sun report that the driver let go of the steering wheel and leapt to his feet when he saw the reptile.
Colonel Jay Naicker said the cause of the accident, on the M25 near Dube village on Wednesday morning, was unknown.
Four women, aged between 27 and 44, died and four others were injured and taken to hospital. All eight were passengers in the minibus.
The bus driver was unhurt. He was not carrying passengers at the time.
The Daily Sun reported on Thursday that when the driver saw the snake the bus swerved into the path of the oncoming taxi.
A woman who did not want to be named told the newspaper she saw the taxi driver jump out of the window.
“He wasn’t injured but then I went closer and saw body parts scattered everywhere,” she was quoted as saying.
Local residents told the newspaper they found the snake and beat it to death with stones.
Naicker said two minibuses were involved and that they were searching for one of the drivers after he fled the scene.