The drinking age should not be raised because getting drunk is fun and 18 and 19-year-olds are not the only problem drinkers, a spokeswoman for the Keep it 18 campaign says.
The reaction follows the release yesterday of the 500-page report by the Law Commission into reducing the harm caused by alcohol. The report made a number of recommendations, including raising the purchase age of alcohol to 20-years.
The Government was considering the report and its recommendations before saying what it would agree to.
Keep it 18 spokeswoman Jenna Raeburn, 22, said today it was a contradiction that 18 and 19-year-olds could work in a bar, vote, get married or become a prostitute and politicians were considering taking away their right to drink alcohol.
There were also benefits of drinking, which were not mentioned in the Law Commission report, she said.
"The fact that people like to drink speaks for itself.
"Going out and drinking, and even going out and getting drunk, can be a lot of fun."
Ms Raeburn said raising the alcohol purchase age would punish the majority for the actions of a few problem drinkers.
ACT on Campus president Peter McCaffrey, 22, said Members of Parliament who wanted to raise the drinking age should reject any votes they receive from 18 and 19-year-olds at the next election.
"If an 18-year-old is not rational enough to be able to have a beer after work with their workmates, how can they possibly make such an important decision as to who should represent them in Parliament?"
Mr McCaffrey said his group believed people should decide whether to drink alcohol or not for themselves, it was "not the job of politicians to save people from themselves".
Young Labour spokeswoman Nicola Wood, 17, said the Government would do better to enforce current law rather than punishing the majority of the 140,000 18 and 19-year-olds who were responsible drinkers.
"Creating a culture of responsible drinking only comes from policy which better enables young people to make positive decisions about how they use alcohol."
Young Greens spokesman Zachary Dorner, 20, said many older people also drank excessively.
"Eighteen and 19-year-olds are not the problem -- drinking is."
Raising the purchase age of alcohol was a "discriminatory solution" and could not address the cultural issues around drinking in New Zealand.
The law was also likely to be flouted, he said.
Mr Dorner proposed restricting alcohol supply and advertising, increasing education and treatment accessibility and community control as the best ways to improve the drinking culture here.
Young Nats president Daniel Fielding, 23, said an 18-year-old has the responsibilities of adulthood so there was no justification for restricting their right to consume alcohol.
Young people were a "convenient scapegoat", he said.
"Solutions need to focus on problem drinkers, not punish all drinkers.
"A blanket measure of raising the drinking age will not change the drinking culture."
At the other side of the age spectrum, Grey Power national president Les Howard said he welcomed the Law Commission's report and hoped the Government would adopt its recommendations.
"The country's alcohol problem needs to be addressed urgently."