The Government's liquor law bill passed its first reading yesterday amid strident criticism from Opposition MPs who said it would do little to curb binge drinking or reduce the harm alcohol caused.

The Alcohol Reform Bill gives local authorities strong powers to decide their own licensing rules, proposes splitting the purchase age to 18 for bars and 20 for supermarkets and liquor stores, puts restrictions on the supply of liquor to minors and extends the description of public places where drinking can be banned.

Justice Minister Simon Power said "legislation alone won't change our excessive drinking culture".

"It can, however, help us develop a safe and responsible drinking culture, supported by robust public education and treatment interventions."

Labour's justice spokeswoman, Lianne Dalziel, said the Government had "gutted" the Law Commission's report which was the basis for the proposals.

"The Government has ignored evidence that at least four other matters had to be addressed - lifting the price of the cheapest alcohol, the excessive commercialisation of alcohol, constraints on marketing New Zealand's number one recreational drug, and introducing stronger laws relating to alcohol and driving."

She said it had caved in to industry arguments.

Maori Party MP Hone Harawira said his MPs would support the bill but didn't believe it would make much difference.

The bill passed its first reading on a vote of 114-3. It has been sent to the justice select committee which will spend at least six months hearing public submissions on it.