Lowering the drinking age to 18 has not led to more binge-drinking or alcohol-related road accidents among young people, researchers have found.

The study, due to be published in an academic journal later this year, shows changes to the minimum purchasing age passed by Parliament in 1999 had no significant impact on the drinking patterns of 15 to 19-year-olds relative to 22 to 23-year-olds between 1996 and 2007.

University researchers used data from the New Zealand Health Survey to ascertain drinking behaviour, then used figures from the ministries of health and transport to examine alcohol-related hospital admissions and road accidents before and after the Sale of Liquor Amendment Act was passed.

Although there was a huge spike in alcohol-related hospital admissions immediately after the law change, reform had little impact on teen drinking behaviour overall, researchers concluded.

The admissions leapt by 75 to 91 per cent among 18 and 19-year-olds, and 43 to 73 per cent among 15 to 17-year-olds and among 20 to 21-year-olds.

When displayed on a graph, however, the data indicated alcohol-related road accidents were steady among all age groups before and after 1999.

The findings, presented recently at a seminar at the University of Waikato by University of Otago professor Steven Stillman, have since drawn a mixed response from medical experts, MPs and concerned parents.

Grant Christey, clinical director of trauma services at Waikato Hospital, said the data was "shaky".

It was rare for hospitals to have "robust" ethanol data on trauma patients stretching back to 1996, and the data set used by Professor Stillman to calculate alcohol prevalence - ICD diagnostic codes - was not entirely reliable, Dr Christey said.

"We don't trust it and we wouldn't produce research on the basis of an ICD 10 code."

Recent trends based on more accurate blood alcohol records suggested the research could still be correct, he said.

"We're still seeing huge numbers of major trauma from road crashes in the 15 to 20 age group, but it seems the alcohol use is slightly higher in the 20 to 24 group, and there is a second peak in the 35 to 40 group."

For Waikato woman Catherine Peary, whose daughter Amy Rose Allen died in an alcohol-related car crash south of Morrinsville in 2010, the findings were not surprising. "The age thing is irrelevant. Young kids are getting alcohol - my daughter was getting it, and adults often give it."

Immediately after her daughter's death, she spoke out about the urgent need to curb the harmful effects of New Zealand's drinking culture.

But yesterday Mrs Peary said the debate was often focused in the wrong direction. "It seems so stupid, because they're not getting to the core of the problem, which is the whole culture. It's not just that they can get alcohol at a certain age. If they raise the bar, then bring it back, you still have the issues that are underlying."