A young motorcyclist has died after a crash involving three other riders.

Emergency services were called to the South Gippsland Freeway in Dandenong South following reports four motorcycle riders had been involved in a collision about 7.15pm on Saturday.

A male aged in his 20s died at the scene.

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One of the three remaining riders was taken to hospital with serious injuries while the other two were also transported to hospital but escaped serious injury.

Victorian police believe the motorcycles involved were travelling north on the freeway headed to Port Melbourne.

Police said the motorcyclist may have been a part of a group of up to 40 riders when the collision occurred.

Major Collision Investigation Unit detectives are investigating with the northbound side of the freeway remaining closed.

Anyone who witnessed the incident or with dashcam footage is urged to contact Victorian police.