Small stores are being encouraged to voice their opposition against the extension of Sunday opening rules for large shops as the government begins its review of the 12-year old laws.

The Department of Trade and Industry (DTI) has asked for the opinions of consumers, businesses and religious groups as part of its assessment of the Sunday Trading Act 1994.

Under the regulations, large shops over 280 metres can only open for six continual hours between 10am and 6pm on Sundays, excluding Easter Sunday.

The DTI claims a review of the laws is required as they have not changed for more than a decade with one spokesman saying it is necessary because "consumers now have greater expectations."

As well as seeking the views of interested parties, trade and industry secretary Alan Johnson has commissioned an independent economic assessment of the impact of relaxing the rules which is due to be published in the spring.

While large retailers unsurprisingly back longer opening hours, groups representing small businesses claim a relaxation of the regulations would threaten the livelihood of local independent store owners. Under the Act, small shops have no restrictions on trading hours.

David Rae, chief executive of the Association of Convenience Stores (ACS), urged independent retailers to communicate their opposition to politicians.

"We know that changing the Act would have a devastating impact on retailers. More than ever before, retailers need to make sure their voice is heard," he said.

"The mail-bags and the email inboxes of each MP needs to be filled with the views of retailers. Campaigning on the ground at local level will be the deciding factor on whether we keep the Act or lose these important restrictions."