MELBOURNE, Jan 9 - The eight-year-old was taken to hospital in a critical condition in November after spending a 30C day accidentally locked in his mum's car when he snuck in playing hide-and-seek.
The youngster was found "unresponsive" by his mother hours later.
"The current policy said three days. We've changed it to say as soon as practical on the day parents are to be notified," Acting Premier and Education Minister James Merlino told reporters on Tuesday.
Government schools would be updating IT and SMS systems in the first half of the year so parents would be getting notifications quicker, he said.
"Thankfully, the Catholic and the independent school system are also supporting this," Merlino said.
"We will be monitoring it, we will be ensuring it's enforced."
The young boy has since made a full recovery.