A 64-year-old Glebe man is in Hospital following a crash this morning at South Hobart.

The crash occurred around 7am when the 64-year-old man was riding a bicycle down Huon Road with a group of three other riders.

A black 2016 Toyota Corolla has attempted to turn left into Hillborough Road, colliding with the cyclist.

The cyclist was conveyed by ambulance to the Royal Hobart Hospital where he remains in a critical condition.

The 28-year-old male driver from Sorell was uninjured in the crash and was conveyed to the Royal Hobart Hospital for mandatory drug and alcohol testing.

The use of alcohol or drugs by either person is not suspected.

Police, including Forensic Services and Crash Investigation Services attended the scene and carried out investigations which are ongoing.

Traffic was reduced to one lane on Huon Road and Hillsborough Road was closed whilst investigations were undertaken.

Police are seeking any person who witnessed the crash or may have dash cam footage of those involved prior to the crash. Information can be provided by calling Tasmania Police on 131 444 or Crimes Stoppers anonymously on 1800 333 000.