Boy hospitalised after being locked in car

A toddler was vomiting and sweating profusely while locked in a car before being taken to a Melbourne hospital.

The boy had just been put in the car in Springvale when the doors accidentally locked about 10.30am on Tuesday, Ambulance Victoria said in a statement on Wednesday.

The temperature outside may have only been 25C but, by the time firefighters smashed a window and rescued him, the boy showing signs of heat stress.

"We moved him to the air-conditioned ambulance and removed his clothes to cool him," advanced life support paramedic Jeff Edwards said in the statement.

"The boy quickly improved and he was taken to Dandenong Hospital in a stable condition."

The boy was one of eight children locked in cars in Victoria on Tuesday, but he was the only one that needed hospital treatment.