Alcohol could be on sale 24-hours-a-day in supermarkets across England and Wales as they aim to take advantage of changes to the country's drinking laws.
New drinking laws have prompted fears of a rise in "binge drinking"
Sainsbury's, Tesco and Asda confirmed a number of their stores have applied for licences allowing them to sell alcohol around the clock.
Current laws limit the sale of alcohol to between 8am and 11pm.
But Alcohol Concern has urged retailers to be responsible, warning the move may lead to a rise in "problem drinking".
The charity urged supermarkets to ensure that they did not offer cheap drink promotions or sell to customers who were underage or drunk.
Sainsbury's said it had applied for applied for 24-hour licences for "the majority" of its 727 stores.
Asda, owned by US giant Wal-Mart, added it was trying to get permits for more than 100 outlets - it added the licences would be extended to match the opening hours of its stores.
Meanwhile, Tesco said the "majority" of its stores would be applying for the extension, in order to offer its customers greater convenience.
The new rules allowing 24-hour drinking in England and Wales come into force in November.