The teenager had boarded the 109 tram in Kew about 1.40pm last Thursday when she noticed a man watching her.

Feeling uncomfortable, the girl got off the tram at Surrey Hills. But police said the man saw her getting off the tram and rushed through the doors before following her down Whitehorse Road.

Detective Senior Constable Christian Arbanovski from the Victoria Police Transit Crime investigation unit said the teenager grew increasingly uncomfortable and tried to escape the man by walking down a side street.

"She's fairly panicked at this stage and she's seen the male crossing the road again to follow her down a side street," he said.

The teenager then ran to a tradesman working in a front yard who told her to hide at the back of the house.