The father of a toddler found dead in a hot car on a suburban Sydney street has been released by police, without charge.

On Friday morning, floral tributes were being left at Railway Parade in Glenfield, in Sydney’s south-west, where emergency services were called a day earlier following reports a child was not responding.

Police arriving at the scene on Thursday afternoon were told the three-year-old had been in the car throughout the day, with temperatures rising as high as 34 degrees.

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The boy’s father raised phone emergency services when he returned to the car. There are multiple reports that he smashed the vehicle’s back window in a desperate attempt to reach his stricken son.

He also began attempts to revive the small boy. Paramedics arrived soon after, but the three-year-old could not be revived.

“The vehicle’s owner, a man known to the child, raised the alarm when he returned to the car,” a police spokesperson said.

Footage from the scene shows distraught people on the ground near the car. A man, who has blood on one hand, can also be seen covering his face and weeping.

The Seven Network is reporting the boy’s visibly distraught father he told police he forgot his son was in the car when he parked it on Thursday morning, and returned to the family home around the corner.

The 45-year-old man was taken to Campbelltown Police Station but was released without charge on Friday.

A crime scene was established and an investigation into the incident continues.

-with AAP