For £2.50, car parking and clamping firms can buy personal records of motorists staying too long on their property.
The DVLA has earned £9m through the practice since 2002. In 2007 alone, it pulled £3.7m by selling the names and addresses of more than 1.3 million registered vehicle owners to private companies.
Mike Hancock, MP for Porstmouth South said: "I think the figures are outrageous. I don't think they should be allowed to sell people's personal details and I think the government should step in now to stop it.
"This is an alarming trend where peole's information is being used to make profits. It's an utter disgrace."
As well as paying £2.50 for an individual's details, which is done by applying in writing, firms can also pay a £3,000 fee to access its database online making it easier to obtain the information.