Man shot dead southeast of Melbourne

A man's body has been found in a shed with a gunshot wound in Victoria's southeast with homicide detectives investigating.

The body of the unidentified man was found in the shed at a property in Baxter in the Mornington Peninsula region before 11am on Saturday.

Police are treating the man's death as suspicious.

A 45-year-old Baxter man, who is known to police, has been arrested and is being questioned.