Narre Warren and Pakenham top the call-out lists for children reportedly left in locked cars in Victoria in 2016.
According to Ambulance Victoria figures, paramedics were called to 1562 cases state-wide last year with nearly 80 per cent of them involving a toddler.
In some cases, firefighters were forced to break into locked cars to rescue children who were then treated by paramedics.
About 20 per cent of the children needed medical treatment with 15 taken to hospital.
The highest suburban callouts – including possible false alarms – were in Narre Warren (30) and Pakenham (27).
Some of the other highest incidences were in Dandenong (20), Berwick (16) and Cranbourne (12).
On 2 February, the State Government launched a Never Leave Kids in Cars campaign to stress the heat-related dangers to children.
Families and Children Minister Jenny Mikakos said it was disappointing that so many people were putting a “loved son or daughter” being put at risk of serious injury or death.
Children were at particular risk because their body temperature can rise up to five times faster than an adult, Ms Mikakos said.
They lose fluids quicker, become dehydrated and can suffer life-threatening heat stroke and organ damage.
Ms Mikakos re-iterated the legal penalties to parents and carers – fines of up to nearly $3700 and up to six months’ jail.
“Hot cars kill – so there are no excuses and no exceptions.”
State Health Commander Paul Holman of Ambulance Victoria said tests had found that on a 29-degree day, the inside of a car could reach 44 degrees in 10 minutes and 60 degrees in 20 minutes.
“Even if you’re just ducking into the shops – you might get distracted or bump into someone you know.
“Time can tick away much quicker than you realise.”
Mr Holman said that some of the callouts were accidents, others appeared deliberate.
He urged parents to keep their keys in their hand as they were getting children and shopping in and out of the car.
