A three-year-old girl has died after she was apparently forgotten on the nursery school bus in left in the boiling hot sun for five hours.

Local firefighters believe that China Kawamoto died of heatstroke in the tragic incident that took place in Makinohara, which is a city in Shizuoka prefecture, southwest of the capital Tokyo, on Monday, 5th September.

The nursery school bus reportedly arrived at the school at about 8:50am that morning and staff found China unresponsive on the same bus at about 2:10pm.

The bus had reportedly been driven by the school principal, unnamed but who is in his 70s, while five other children also took it, along with an unnamed staff member, also in her 70s.

The young girl reportedly had a high body temperature when she was found inside the bus and when she was taken to hospital.

The temperature peaked at 30.5 degrees Celsius in Makinohara on Monday, at around 1pm, according to Japanese media.

Police are investigating and may reportedly open a case for negligence.