Vic woman killed crashing into letterbox

An elderly Melbourne woman has died after she crashed into a letterbox while reversing out of her driveway.

The 78-year-old was thrown from her car, police say.

She reversed out of her driveway in Blackburn North, continued across the street and hit a concrete letterbox at the home opposite, police believe.

The woman was flung from her car and died at the scene on Slater Avenue about 11am on Saturday morning.

The exact circumstances of the crash are being investigated and police are calling for witnesses.