A man has been arrested after a body was discovered on the roadside in a suspected hit-and-run.

A passerby found the body of the 40-year-old Traralgon man about 9am on Thursday on the Princes Fwy overpass above Princes Dr in the southeast Victorian town of Morwell.

Investigators believe he was struck by a vehicle sometime between 1am and 9am, with the driver leaving the scene.

Know the news with the 7NEWS app: Download today

Detectives urged Traralgon-bound motorists who were on the Princes Fwy during that time to check their dashcams.

“Motorists may have inadvertently captured the man as he was walking in the area, or the vehicle involved,” police said.

A 28-year-old Lakes Entrance man was arrested in Bairnsdale on Thursday afternoon and was interviewed by police, but has since been released pending results of an ongoing investigation.

Anyone with information or footage is urged to come forward.