Drivers have been warned they will face fines if they stay longer than the time limit allowed at Merry Hill.
Thousands of shoppers flock to the Brierley Hill centre every week and have been told to be aware of the changes.
Visitors can now park for four hours only on two main car parks, after which they could face fines.
Signs have been placed on the car parks warning that ANPR cameras are now operating, tracking when vehicles enter and exit the site.
The new restrictions apply to Merry Hill's "red" and "blue" car parks and the changes come after bosses decided to make more space available for staff there.
Changes to staff parking, to free up more space for shoppers, have proved controversial and sparked a backlash from workers.
Under the new system staff can only park for two hours in customer parking spaces at the shopping centre.
The workforce has been allocated specific sites to use as a result, for which they need parking permits.
More than 1,000 people have signed a petition against the move, which was labelled as "impractical" and "unfair".
Bosses at Intu, which runs Merry Hill, hope most shoppers will not be affected by the changes and that four hours will be enough time for most visitors. However, those hoping to stay for much of the day will have to park at other car parks on the site, which remain free at all times.
The "red" and "blue" car parks serve the upper and lower retail parks. Others serve M&S, Argos, Debenhams and the Odeon cinema.
A Merry Hill spokeswoman said: "Parking at Intu Merry Hill is completely free of charge for all shoppers. To ensure that there are enough spaces for our shoppers we have introduced a four-hour time restriction on just two of our thirteen car parks, at the upper and lower retail park.
"Shoppers who are visiting us for longer than four hours are free to park on any of our other car parks for as long as they wish."