The accident happened on the Bole Road. His car was reportedly mangled in the process, a leading member of the NPP Asare Otchere Darko wrote on his facebook wall.
He has been flown to Accra and is said to be receiving treatment.
It is not yet clear how the accident happened, but according to Otchere Darko, Bawumia was able to walk from the plane before being whisked from the airport to the hospital in pain.
His aide Kwabena Boadu is also believed to have sustained some injury after the accident.
They are both receiving treatment and doctors say they will be fine.