Parents who supply alcohol for end-of-school celebrations may believe they are exercising control over their kids' drinking, but in reality they could be aiding riskier and heavier consumption.

Tina Lam is a research fellow at Curtin University's National Drug Research Institute who is investigating risky drinking in young people.

She told ABC Radio Perth that surveys of drinking behaviour at Schoolies events (known as Leavers Week in Western Australia) showed teenagers did not limit themselves to drinking the alcohol they got from their parents.

"The most common reason why people might buy their children alcohol would be to control how much the child drinks — or think they control it," Dr Lam said.

"They might also do it to be a friend to their child, to give them some alcohol so maybe they will have something to give their friends, and that will give them some social kudos in that group."

Young people don't limit themselves to drinks from parents

Dr Lam's surveys of 400 Western Australian school leavers found about 25 per cent had been given alcohol by their parents.

"Most of those kids who received alcohol from their parents, two-thirds of them actually went on to top up that alcohol with other sources," she said.

"It definitely wasn't a matter of drinking only what their parents provided and therefore what the parents perceived them to be drinking.

"Even if they got alcohol from their parents and only drank the alcohol they got from them, they were still drinking really high quantities."

Teens who attend celebration hotspots drink, on average, 15 standard drinks a day. ( ABC News )

Dr Lam's research found at school leavers' celebrations, regardless of where they got their alcohol from, on average the teenagers drank 15 standard drinks a day.

"Even if they got the alcohol from their parents, from their friends, from a combination, it was roughly the same quantity each day and way beyond the low-risk quantity," she said.

Alex (parent): I supplied them with vodka. I just opened the bottles very carefully and made a 50/50 vodka/water mix. They will get it anyway. This way they drink less than they think. And at that age, they can't taste the difference.

Karen: My school leaver is already 18. I just have to trust I've taught her well and she's smart enough to do the right thing.

Talking about safety more effective than supply

Dr Lam suggested that rather than providing alcohol, parents who wanted their children to limit drinking might be better having a talk with their kids about safe drinking, rather than trying to control the supply.

"Over a broad period of time it's quite hard to identify what the impact of a parental discussion is on alcohol and drug use, but specifically within the context of leavers, we did find some small positive effect," she said.

"We don't know exactly what they were talking about, but we do know it was some sort of safety discussion around alcohol.

"It might have been promoting drinking water between drinks or letting a friend know when they have had too much."

A parental chat about safety and the risks of heavy drinking can be beneficial. ( ABC News: Candice Marshall, file )

Dr Lam has produced a factsheet for parents whose children are attending end-of-school celebrations.

Denise: No point in only talking about it just before Leavers. The conversation and expectation needs to happen in Year 11, as for some they are adults by halfway through Year 12.

Tom: We have two teenagers who, whilst are not at school leavers age yet, are so not interested in the prospect of drinking and grossed out by cigarettes. We as parents drink in front of them at dinner and thought that would be an influencer, but doesn't seem to have. I do think there has been a shift due to greater exposure through school education.

Overall teen drinking in decline

Dr Lam also pointed out that teenagers who chose to attend such celebrations were a self-selecting group and not reflective of overall drinking trends among all young people, where alcohol and drug use was in decline.

"The young people who were drinking a lot during grade 12 are going to go on to Schoolies and they are going to choose a hotspot like Dunsborough or Rottnest," Dr Lam said.

"The kids who are drinking more moderate levels or choosing not to drink at all during high school, they are choosing to go to other places or choosing not to celebrate Leavers at all.

"Those low-risk drinking kids are actually part of the major abstention trend that we are currently in and have been in the past 15 years or so.

"More and more young people are choosing not to drink."