The wife of a key Taiwan politician is in coma after the couple were injured in a road accident, according to hospital reports on Monday.

Taichung Mayor Jason Hu (R) and his wife Shaw Hsiao-ling.(File Cnsphoto)

The condition of Shaw Hsiao-ling, wife of Taichung Mayor Jason Hu, had improved but was still critical after doctors put her on a life support system, said a source with Taiwan Chi Mei Hospital in southern Taiwan.

The couple, and two aides, were injured in a car crash on Saturday night as they were heading back to Taichung after a support campaign for the opposition candidate, Huang Chun-ying of the Kuomintang, for the mayoral election of the southern city of Kaosiung.

Hu suffered slight injuries to his head and hands, but Shaw was thrown from the car and caught beneath the overturned vehicle, according to local media.

Doctors have amputated Shaw's smashed forearm and removed her spleen during emergency surgery soon after the accident, local media reported.

Police investigations reportedly show the accident was caused by another car that hit the mayor's vehicle.

Editor: Donald