Shops will be able to extend normal Sunday trading hours during the Olympic and Paralympic Games in summer raising concerns that staff will be forced to work longer.
The legislation that was announced in March's Budget and given royal assent today means some shops will be exempt from current Sunday trading restrictions on eight Sundays during the Olympics.
Labour's David Wright asked why some shop workers will have to "work longer" during the Olympics on a Sunday "when they want to be at home with their families watching the Games."
Business Minister Mark Prisk said: "Retail workers will keep all their legal protections, such as the right to opt-out of Sunday working but many will want to take the opportunity to work extra or different hours."
He sought to calm fears that the move may a test for a permanent relaxation of the rules by stating the measure was temporary.
The legislation will only apply in England and Wales.