Dirty underwear and graphic pornography left in Melbourne mail boxes

Dirty underwear and porn have been left in the letterboxes of a number of businesses in Melbourne.

Police say they are hunting a man who's been targeting businesses in Sandringham for the past 12-months, slipping his soiled calling card through their mail slot.

He's also been leaving graphic pornography.

The bizarre behaviour was only reported to police recently and they are appealing to other businesses that may have been targeted but haven't come forward.