A drunk executive of a well-known cosmetic clinic was arrested in Bangkok after his Mercedes-Benz struck a parcel delivery rider, knocking her off a flyover onto Rama IV Road below, where she died.

The crash occurred on the Thai-Japanese bridge above the Henri Dunant intersection on Rama IV Road. Police were alerted at 2.35am on Thursday.

Police and rescue workers found the Mercedes on the bridge with damage to its left front. The driver was later identified as Punnamee Satjamongkol, 44, an executive of the Pornkasem clinic.

The motorcycle was found on the bridge with its right rear badly damaged.

The bike rider was found dead on Rama IV Road below with neck injuries and fractured legs and arms. She was later identified as Chawee Arsaisong, 44. 

Mr Punnamee told police that he had just left a party and was on the way home. He was travelling on the bridge heading to Hua Lamphong when his car hit the bike.

Police took Mr Punnamee to the Pathumwan station for an alcohol breathalyser test. He was found to have 119 milligrammes per decilitre (mg/dL) of alcohol in his system, which far exceeds the legal limit of 50.

Police charged him with drunk driving and reckless driving causing death.