Authorities were called to Maddox Road in Newport just after 2.45pm after an "incident" involving a child.
The black Kia minivan was loaded onto a tow truck and removed from the scene at around 6:20pm on Monday evening.
The young boy who is now clinging to life in hospital was found in the family Kia Carnival on Maddox Road in Newport, Melbourne, at around 2.45pm on Monday and had spent several hours inside the vehicle.
She found him inside at 2.45pm.
The child, whose age and gender is unknown, has been transported to Royal Children's Hospital with critical injuries.
'She has driven to work and parked her vehicle without knowing he was in there'. "Police are treating the incident as an accident".
The auto is taken away on a tow truck.
A detective takes a photo of shoes after the child was taken to hospital.
It has been confirmed the boy was the son of a staff member at the nearby Newport Gardens Primary School.
The boy's school is less than four kilometres from where he was found on Maddox Rd, Newport.
The boy's school is less than four kilometres from where he was discovered in the auto.
Police Leading Senior Constable Lee Thomson said the boy was "unresponsive" when he was found.
His classmates are also struggling to cope with the tragedy, and both the boy's school and the public school where his mother works are offering their communities counselling.
"Counselling is being made available to students and staff at St Margaret Mary's Spotswood after an incident yesterday when a member of the school family was found in a auto", he said.
In summer, it can be up to 30C hotter than outside. Police have blocked off Maddox Road as they investigate.
The auto before it was taken away on a tow truck.
"It can be really inconvenient to get them in and out of baby seats, parents are really busy, but a child left in a vehicle can easily die". 'It's sad whichever way it happened - especially when kids are involved'.
The city has sweltered through a brutally hot spring day with the mercury hitting 33 degrees.
Temperatures in Melbourne struck 32C about 3pm.
But incredibly the eight-year-old managed to sneak back inside the family's black Kia Carnival van and hide from his mum, Herald Sun reported.