A glitch in the City of Toronto's parking machines may be costing the city $1 million per year in lost payments, CBC News has learned.

It appears that some people are using expired, pre-paid credit cards which allow them to obtain hourly parking permits for free.

The machines — more than 17,500 of them in the city — don't check to see if there's any credit left on the cards before issuing the parking receipt.

The Toronto Parking Authority acknowledges the problem — and admits it stretches back to 1998. At $1 million per year in losses, that adds up to about $10 million in total.

The TPA said it is in the late stages of testing new technology to correct the problem.