Baby boy found dead in car

A baby boy has been found dead in the back of a car outside a Victorian home.

The 22-month-old was found inside a Toyota Hilux on Acacia Drive in Kyneton about 3pm on Thursday.

Police have been unable to confirm reports the home is a childcare centre and the baby's mother discovered the boy after arriving to pick him up.

"That's all part of our inquiries at this stage," Inspector Ryan Irwin told reporters.

"I understand the boy has been found by a family member and paramedics were called and obviously there were attempts made to try and revive the child."

Insp Irwin said homicide squad detectives would oversee the investigation.

Temperatures reached 31.6C in the Kyneton area on Thursday.

Ambulance Victoria would not comment on the latest case, but has issued repeated warnings against leaving children in cars.

In the first five weeks of the year, paramedics were called to 200 cases.

Ambulance Victoria group manager Brett Drummond has said it's frustrating the message is not getting through.

"It's never OK to leave a child in a car, no exceptions, no excuses," he said on February 6.

The state government has promised to increase penalties for leaving children in hot cars, with fines up to $3700 and jail time increased from three months to six months.