Police will also be able to issue spot fines to anyone drinking alcohol in a liquor ban area, such as in downtown Auckland.
Some of the changes targeted irresponsible marketing of alcohol.
Justice Minister Judith Collins told the Herald: "Communities have told us they are concerned about the impact of alcohol advertising and sponsorship. Many people worry that marketing can glorify drinking, or affords it unwarranted status given the harm that can occur when people overindulge."
Bars would no longer be able to offer "2-for-1" deals or deep discounts outside a store, in brochures, or in social media.
Some supermarkets were already using advertising designed to get around these rules, such as promoting a "beer sale week" or "wine sale week".
It would also be illegal to use promotions which led people to believe they would get a discount of 25 per cent or more.
Hospitality Association deputy chief Sara Tucker said: "We think we can probably still do happy hours, as long as happy hours don't suggest a 50 per cent discount. It's an interesting question - if you see happy hour do you think 50 per cent discount?"
Asked whether happy hours would be abolished, Mrs Collins said: "It depends on the promotion."
Police, the Health Promotion Agency and the Hospitality Association were working on guidelines for bars and restaurants.
Some of the changes
*Parents or guardians must give express consent for minors to drink, or risk a criminal offence punishable by a $2000 fine
*Bars, clubs and restaurants must close between 4am and 8am, and stores between 11pm and 7am
*Police can issue spot fines for people who drink in a liquor ban area
*Changes come into force December 18