A 62-year old man was taken to Dunedin Hospital for the treatment of minor injuries, a St John spokesman said.
A witness told the Otago Daily Times the cyclist collided with the car's door just after the driver had opened it.
Members of the public rushed to help the man, who was lying on the road but conscious, while emergency services were called, the woman said.
Police and St John arrived just before noon.
A police spokesman said officers spoke to both parties involved, but no further action was taken.