Four young children were allegedly left inside a locked car in Sydney's west on Wednesday afternoon, as the mercury hit its peak at 40.9 degrees.
NSW Police were called to a car park at an office supplies store on Canterbury Road, Bankstown, at 3pm, after being alerted by concerned passersby.
The four children, aged 9, 8, 7 and 6, were helped from the vehicle by witnesses and were uninjured.
Temperatures soared in Sydney on Wednesday during the first heatwave of 2017, with temperatures reaching 42 degrees in Western Sydney and 38 degrees in the city in the afternoon.
Wednesday was the fifth day of this summer that temperatures exceeded 35 degrees, the most since 1991-1992.
Police warn that on a typical summers day the temperature inside a car can reach 50 to 60 degrees, even with the windows rolled down.
The driver of the vehicle, a 44-year-old woman, had left the scene when officers arrived, but later assisted police at Bankstown police station.
She is expected to appear in Bankstown Local Court on February 22, charged with leaving children/young persons in a motor vehicle causing emotional distress.