A man has been arrested after another man was found shot dead at a home in Melbourne's west overnight.

Emergency services were called to Oxford St, Sunshine North, about 12:40am where they found a man dead with gun shot wounds.

Police arrested a 56-year-old man at the scene, who is assisting the homicide squad with the investigation, police said.

The dead man has not been formally identified but police believed the two men knew each other.

Anyone with information about the incident has been urged to call Crime Stoppers.