A motorcyclist has died following a single-vehicle crash on the Monaro Highway south of Cooma on Friday afternoon.

About 1.20pm, emergency services responded to reports a motorcycle had crashed at Rock Flat, about 20km south of Cooma.

The rider — a man believed to be in his 40s — died at the scene before emergency services arrived.

Police say the man was travelling with a group of motorcyclists when the crash occurred. No other vehicles are believed to have been involved.

The Monaro Highway remains closed in both directions, with motorists advised to avoid the area as investigations continue.

Anyone who witnessed the incident, or who has dashcam or mobile phone footage, is urged to contact Crime Stoppers.

Further details about road closures here.