Mike Devlin, of Narre Waren South, said he was doing the "right thing'' by trying to keep off the road but was paying the price.

Mr Devlin's Holden Commodore is parked at the Berwick railway station's southern car park from 7am to 7pm on weekdays as he commutes to work in North Melbourne.

About four months ago, he got behind the wheel to drive home and the petrol warning light started flashing.

Although surprised, he managed to get to nearby petrol station and fill up.

Mr Devlin realised he had been the victim of petrol thieves when the same thing happened a week later.

Police checked his car and told him the catch on the petrol cap had been deliberately broken.

On May 23, his car's rear numberplate was stolen and used in a petrol station drive-off.

Mr Devlin said Connex told him motorists parked at their own risk and the car park was owned by the Department of Transport.

The department said there was not enough money in the budget to upgrade security.

Frustrated, Mr Devlin spent $25 on a petrol cap with a lock and $200 on new numberplates.

"The only thing that can go next is the car,'' he said.