A woman and man are dead following a shooting in Rosebud on Victoria's Mornington Peninsula.

Emergency crews were called to Adams Avenue just about 4.25pm today, where police found the pair inside a car.

The woman was found dead inside the car. (9NEWS)

An Ambulance Victoria spokesperson said they were treating a second person who was in a serious condition. He later died in hospital. (9NEWS)

The woman was found dead, and the man, believed to be aged in his 80s, had sustained life-threatening injuries from a gunshot wound.

He was taken to the Alfred Hospital where he died overnight.

The exact circumstances of the shooting are being investigated but police say they are not looking for anyone else.