Repeated approaches by a male cross-dresser to people on the street, including teenagers, have Canberra police worried.

They say a man, aged somewhere between mid-20s and early 30s, has committed indecent or intimidating acts on each occasion.

Each time he was dressed in women's clothing.

The first known occasion was on August 31, 2010, at about 9pm, when a 14-year-old boy was approached by a man driving a late-model silver BMW in suburban Rivett.

The driver got out of the car and tried to talk to the teenager before exposing himself and committing an indecent act.