Auckland needs to copy Sydney's one-way door policy for central city bars if it wants to defuse the culture of late-night, booze-fuelled violence, police say.
They are lodging a legal challenge to Auckland Council's provisional rules around closing hours, which say the central city bars can open until 4am.
A court date has not yet been set.
The move comes after four brawls erupted on Saturday night, where two people were hospitalised and two others arrested.
"Unfortunately, this type of violence is not unusual in the CBD, K Rd and Ponsonby," said Inspector Gary Davey.
There was alcohol-fuelled violence on Friday and Saturday nights, characterised by serious assaults, fighting and disorder in the early hours.
"There is a tipping point in the CBD around 1am when the fun and laughter takes a decidedly nasty turn, with intoxication levels increasing and fights and assaults occurring in the same areas in the CBD," Insp Davey said.
The council had a responsibility to address the problem but the opening hours were disappointing, he said.
"Yet the proposed closing hours of 4am in the CBD and 3am in the rest of the city allows the current level of harm to continue.
"You only need to look at Sydney, which has had similar issues to Auckland, to see what difference a change in closing times can make."
Insp Davey said Sydney introduced a 1.30am one-way door policy in 2014 and all bars close at 3am, leading to a 40 percent drop in alcohol harm.
"This is what Auckland needs if we want to stop the high numbers of people ending up in our hospitals after a night out."