HOMICIDE detectives are probing the death of a baby girl who was allegedly left in a car and suffered heat trauma.

The Herald Suncan reveal detectives believe the 10-month-old baby was left in a locked car with its windows shut at a Glenroy house.

Police said heat was being considered as a factor in her tragic death.

The temperature in Melbourne was 29C at 2pm last Saturday when an emergency phone call was made.

It is not known how long the child was in the car.

A 20-year-old woman was interviewed by police and released without charge.

Paramedics arrived at the scene in Glenroy to treat the girl after responding to an emergency call that a child had stopped breathing.

Officers said they found the child dead and the State Coroner had conducted a post mortem.

The results are to be sent to the homicide squad.

It is the third time in a year detectives have probed deaths involving babies. No charges have been laid in the other two cases.

In New South Wales, a 30-year-old Toongabbie woman has been charged with manslaughter after allegedly leaving her daughter in a car.

The child, 22 months old, is alleged to have died of dehydration.

About 750 Victorian children a year are rescued from locked cars.

Last month, medics warned parents to be vigilant after reports of five cases in just one day of children being left in vehicles.

In one recent case a mother had to call for help twice.

Tests by Ambulance Victoria have shown that, on a 29C day, the inside temperature of a car can rise from 20C to 44C in 10 minutes. Another 10 minutes and the temperature can reach 60C.