Whangarei mayor Stan Semenoff is calling on all political parties to endorse a two-tier drinking age in a bid to reduce drinking by teenagers.
Several street brawls in Whangarei have involved drinking teenagers.
One resulted in at least four arrests when a street fight later spilled over into the city hospital's carpark while two young men were treated for injuries caused by bottles.
Mr Semenoff is suggesting 18-year-olds could still drink in bars and clubs where they are supervised by bar staff but be unable to buy alcohol at liquor outlets.
He believes the "vast majority" of people know politicians made a big mistake when they lowered the drinking age to 18, especially when supermarkets and liquor wholesalers heavily discounted prices.
"Allowing teenagers to buy unlimited quantities of cheap alcohol has done nothing for society but it's doing great harm to teens," he says.
Police had told him there was a marked difference in behaviour between 18-year-olds and 20-year-olds "and any parent will tell you there is an enormous difference between 16 and 18".
Allowing 18-year-olds to buy cheap beer and alco-pop drinks by the dozen is putting a lot of alcohol into the hands of 16-year-olds and younger, Mr Semenoff says, while home drinking by teens contributes to street disorder and violence.
Mr Semenoff has already proposed a 2 am one-way-door policy for central Whangarei bars and nightclubs, and is investigating the introduction of a bylaw to close inner-city carparks at 3 am.
He says the moves are an effort to "return civilisation to the streets".
Police say there is a major problem with young people drinking at home and then going into town to hang around carparks.
Bar owners say young people drink in carparks rather than pay bar prices.
Mr Semenoff has discussed his proposal to raise the off-licence age to 20 with Whangarei-Kaipara police area commander Inspector Paul Dimery.
Mr Dimery supports the idea of a change, believing it could help reduce the problems resulting from home drinking.
Mr Semenoff said he appreciated no politician wanted to risk losing the 18-year-old vote but the issue could no longer be avoided.
"Parliament found it simple enough to ban party pills, and now it can do even more for youth health and safety by banning bulk alcohol sales to under 20s."
Whangarei mayor Stan Semenoff suggests a two-tier drinking age
* 18 for drinking in bars and clubs
* 20 for buying alcohol from liquor stores and supermarkets