New laws banning adults from supplying alcohol to children in a private setting without their parents' consent come into effect on November 20, 2015.
The State Government's secondary supply laws impose a maximum fine of $10,000. A radio and online advertising campaign informing the public of the changes begins today.
Racing and Gaming Minister Colin Holt said the laws empowered parents who did not want their child exposed to alcohol.
"It is not the Government's intention to reach inside the private homes of families but to tackle those who disregard another parent's wishes or responsible practices when supplying liquor to kids," he said.
"There are already laws preventing people supplying alcohol to under 18s in public places, including licensed venues. Secondary supply laws are designed to be complaint-driven and prevent anyone providing alcohol to under 18s without parental permission in a private setting."
Mr Holt said teenagers who had recently turned 18, or would do so in coming months, needed to be aware of the changes.
"Turning 18 entitles a person to a number of rights and privileges but also comes with increased responsibility," he said.
"If you're an 18-year-old and you supply someone who is under 18 with alcohol then you must have permission from that person's parent or guardian."
Police Minister Liza Harvey said previously a parent was powerless if their child consumed alcohol without their permission.
"This legislation is as much about deterring an underage person from drinking - parents are encouraged to explain to their child that someone is committing a serious offence by handing them alcohol without the parent's permission," Mrs Harvey said.
"If a parent's underage child comes home from a party affected by alcohol parents will be empowered by this new legislation to make a complaint to the police."
Racing and Gaming Minister's office - 6552 6100
Police Minister's office - 6552 5900