Off-licences may now only sell drinks between 10.30am and 10pm on weekdays, and from 12.30pm till 10pm on Sundays.
The law – which also gives police greater powers to seize alcohol where they fear public disorder, and allows test purchasing – was also intended to force supermarkets and convenience stores to display alcohol in a partitioned-off section of the premises.
But the Irish government has put the plans on ice while it waits for a voluntary industry code to emerge.
Retailers who sell alcohol to children will face tougher penalties and stores will be banned from using incentives such as loyalty card points to encourage consumer spending.
The new legislation also allows retailers to apply to the courts for a wine-only off-licence.
Ireland’s National Off-licence Association has expressed concern that the changes to opening hours were introduced at short notice.