Melb mag seller with cerebral palsy robbed

A magazine vendor with cerebral palsy has been robbed on a busy street in Melbourne's CBD in front of passers-by who didn't know what was happening.

The woman was selling the Big Issue magazine in front of a fast food outlet in the afternoon 10 days ago when a man approached her, wiped her face and then rummaged through her belongings, Victoria Police say.

The woman, who was unable to alert passing pedestrians due to her medical condition, could only watch as the thief then slipped her purse into his back pocket and walked off.