Parents and caregivers are ignoring warnings about leaving children in cars on hot days, Kidsafe ACT chief executive Eric Chalmers said.
Children's advocates have issued a warning to Canberrans about the "dangerously high" temperatures the interior of a car can reach, particularly in the extreme heat forecast for the capital.
Kidsafe ACT, ACT Children and Young People Death Review Committee and ACT Policing are asking all Canberrans to be vigilant, know the dangers and take notice of what's happening around them.
Mr Chalmers said following interstate news reports of children being left in hot cars, it was a timely and seemingly simple reminder to not leave children in cars over summer.
"The temperature inside a parked car can be more than 30 degrees hotter than outside the car," he said.
"That means that on a 30 degree Canberra summer day, the temperature inside the car can reach over 60 degrees, and the temperature rises quickly."
Children have died from being left in cars alone, Mr Chalmers warned.
"Recent media reports [from interstate] highlight that parents and caregivers are still ignoring warnings about the risks of serious heat related injuries or death to children who are left unattended in cars during hot weather."
ACT Children and Young People Death Committee chair Margaret Carmody said the message is clear.
"Never leave children alone in cars, always take children with you," she said.
"Children can quickly suffer dehydration and serious brain injury. In hot conditions, children may suffer organ failure and die from heat exhaustion and dehydration if left along in a hot car."
"Leaving the windows down a few centimetres has little effect and only causes a slight decrease in temperature," she said, even if it was for a short time.
She said even when travelling in a car, carers should ensure children have enough to drink and windows should be shielded to protect from the sun.
Ms Carmody said if bystanders see a child left alone in a car, call Triple 0 immediately and emergency services will provide advice on what to do.
If the car is unlocked, open the doors and shield the windows from the sun until emergency services arrive, she said.
A spokeswoman for ACT Policing said if contacting emergency services in this situation, tell police as much information as you have, including your location, details about the vehicle and how old you think the child is.
"These situations are considered emergency priority situation and resources will be dispatched immediately," the spokeswoman said.