The State Government has introduced changes to the Children, Youth and Families Act 2005, which will double the jail time for leaving a child unattended.

Children and Early Childhood Development Minister Wendy Lovell said the changes would also increase the maximum fine from $2214 to $3690.

"Despite an awareness campaign with Kidsafe Victoria earlier this year, a significant number of parents still leave their children unattended," she said.

"This is especially relevant ahead of months with extreme weather, when leaving a child in a hot car - even for a few moments - can have devastating results."

Horsham Inspector Trevor Ashton welcomed the new penalties.

"When it comes to the preservation of life and the responsibility of parenting, these penalties are most applicable," he said.

"As a parent myself, I cannot understand why parents would ever take the chance or even consider leaving their children in a car."

Mr Ashton hoped the new penalties would deter irresponsible parents.

"With the introduction of tougher sanctions, those who even contemplate it will hopefully think twice," he said.

Wimmera Base Hospital Yandilla nurse unit manager Hilton Jones said being locked in a car was unbearable for people of all ages.

"Heat stroke can have catastrophic effects on the brain," he said.

"If anyone sits in a car on a hot summer's day, they won't be able to put up with it.

"It doesn't matter how old you are - whether you are a child or an elderly person - being locked in a car is disastrous."

Ms Lovell said parents could lose track of time while shopping or unloading their car, or did not want to wake their child while they were sleeping in the back seat.

"Whatever the reasons, there's simply no excuses," she said.

"The State Government is taking decisive action and sending a clear message to parents that it is never okay to leave a child unattended in a car."

Ms Lovell said Ambulance Victoria was called to about 1000 cases a year of children left in cars.

"Ambulance Victoria research has found that on a 29-degree day the temperature in a locked car rises to 44 degrees in 10 minutes and to 60 degrees within 20 minutes," she said.