Drunk patrons will not be allowed in bars from next week, and if they are caught, the bar-owner will face a fine of up to $5000.
Police will also film punters, to prove their intoxication.
The new rules are among tougher alcohol measures under the Sale and Supply of Alcohol Act which take effect from December 18 and are intended to reduce alcohol harm in the community.
A 4am closing time for all on-licence premises has been well publicised, but other changes are not widely known.
These include police having the power to ban shot-glass drinks or the use of glass vessels after a certain time, and $250 on-the-spot fines for people who drink in a public place or use a fake ID.
Bars are now forbidden to serve intoxicated people. Under the new law, drunks will not be allowed to be in a bar and the bar-owner can be fined up to $5000 for any breach.
Police already patrol bars, but drunks will now be judged by tougher standards and officers will have video cameras at the ready to film them, said Inspector Gary Davey, of Auckland city police.
The film would be given to the Alcohol Regulatory and Licensing Authority - a district court judge and three other members - which could impose fines.
Said Mr Davey: "Police will be moving towards video-based evidence. So rather than just the police officer's word against the licensee's word ... it's to show the authority for them to make up their own mind.
"We're trying to establish a level of evidence we sometimes have struggled with in the past when people have disputed whether they're intoxicated or not."
Two cameras had been bought for the city's enforcement team, Mr Davey said.
The filming would not be done covertly.
Filming had been used occasionally, but "not on a consistent basis".
Guidelines had been agreed with the industry to help determine who was drunk and who wasn't.
The definition of intoxication had changed, Mr Davey said.
"You can have less to drink now and still be deemed to be intoxicated for the purposes of this act. In the past, it had to be quite a high level of intoxication. It's brought that level down now."
The criteria used to establish intoxication are: appearing to be affected by liquor, impaired behaviour, impaired co-ordination or impaired speech.
Someone who fails two of these tests will be considered intoxicated.
Auckland Council's manager of alcohol licensing, Rob Abbott, said licensing inspectors would also inspect bars. Unlike police, they would not have to identify themselves on entering licensed premises.
"This means they can make some initial observations ... while remaining incognito."
Hospitality New Zealand chief executive Bruce Robertson said the changes were significant, and members were worried about several compliance issues.
"There's a risk to their livelihood in terms of the three-strikes-and-you're-out [penalty]," he said.
"They [regulators] have wide powers to impose conditions. The industry is looking for the enforcement agencies to take a reasonable approach and not apply conditions that are unreasonable or won't genuinely make a difference to reducing alcohol harm."
Police filming patrons was not something he wanted to see happen often. "There would be issues around privacy, I suspect ...
"Again, we are looking at agencies to take a practical approach to this - their approach should be to get compliance, not prosecutions."
People should be aware of the pressures the industry was under.
"If they are asked to leave, they are being asked to leave because they have got themselves into a state which is putting the bar at risk."
Bar-owners sign up to support changing times
Auckland bar owners have acknowledged the changing hospitality landscape by signing up to a scheme that aims to raise standards without the threat of enforcement and fines.
The SuperCity Host Charter commits operators to responsible host standards beyond their legal obligations and is being trialled by 38 central-city Auckland bars. The trial has five months to go.
Simon Ansley of Pack and Co, which runs Libertine, La Zeppa and Neighbourhood, said the charter was a "step up from the legislation" and was a way for the industry to be part of the solution, not the problem.
"We all understand that New Zealand has a problem with alcohol consumption, so we see this as a positive step."
He hoped preventive measures could be put in place so there was less "ambulance at the bottom of the cliff sort of stuff".
Under the charter, bar-owners have to show they manage venues responsibly, and share best practice and information.
A code of conduct also sets out what licensees - and patrons - can do, and is displayed in the venue.
Andrew Roberts of Longroom, in Ponsonby Rd, said patrons would have to change, as the days of "getting drunk and ripping your shirt off" were over.
If a group of six arrived and one was considered drunk, the group would not be allowed in. "We can't let that happen."
Mr Ansley said staff in good venues were trained in everything from first aid to host responsibility, and were determined to create safe, enjoyable environments for patrons and employees.