An investigation has been launched in Sydney over the death of a baby who was left in a hot car.

The 22-month-old baby boy was left inside a parked car outside his home in the suburb of Chester Hill yesterday. He was being cared for by relatives while his mother was out at the time, reports 9 News. The family members noticed that he was missing and began to search for him. He was found unresponsive in the car and brought inside. It is not known how long he was in the vehicle. Emergency services were called and paramedics attended the scene but were unable to save the boy's life. His mother arrived home to find that police had cordoned off the house and learned of the tragedy. She was seen by neighbours breaking down in front of police. Temperatures in the area rose above 30 degrees yesterday. Australia has seen extremely hot weather since the start of the year, with January named the country's hottest month on record. In a statement, the family described the one-year-old as a gorgeous and happy child. "We are all in shock and devastated with the loss of such a gorgeous happy little boy. "We are all just trying to support (his mother) Sam the best we can." New South Wales police have opened an investigation. "The child had been left unattended, we're still looking into the circumstances surrounding his death," a police spokesperson said.