AN eight-year-old girl has died after a limb from a gum tree fell on her and three others at lunchtime today in the playground at Pitt Town Public School.
A parent of one of the children who witnessed the accident told the Gazette her son was sitting inside one of the classrooms looking outside when he heard a massive crack and then saw the large branch fall and hit the students.
"It was right at lunch time and if it happened seven minutes later there would have been about 50 to 60 kids playing under that tree," she said.
According to the parent, the tree had been inspected recently and there were no concerns about its safety.
A five-year-old kindergarten girl and a male teacher in his 50s are also believed to be in a serious condition, according to Hawkesbury police.
A boy aged 6 has suffered minor injuries.
The incident is believed to have occurred around 1pm.
When the Gazette arrived at the scene, police and other emergency crews including ambulance paramedics were seen attending to the injured.
A Gazette reporter at the scene said parents were crying and comforting each other outside the school.
Hawkesbury residents have since taken to the Gazette Facebook page to offer their condolences.
"This is devastating. The little girls family and friends are in my thoughts," one woman posted.
"Rip little darling," another commented.
Police are now investigating the incident.
Pitt Town Public School students and staff will be offered counselling.
As the injured were transported to Westmead Hospital by road ambulance, parents were seen arriving at Pitt Town Public School to pick up their children.
An eight-year-old girl is believed to be in a critical condition while another child is said to have suffered a fractured arm. A male teacher in his 50s was also treated for head injuries.
Detectives have since arrived at the scene.
Police have confirmed that three of the injured were taken to Westmead Hospital while the fourth was taken to Hawkesbury Hospital.
The tree was located between demountable buildings in the playground.
A Department of Education and Communities spokesperson has said counselling we be offered to students and staff at Pitt Town Public School following this afternoon's incident.
The spokesperson said two students and a staff member were conveyed to hospital.
The Department has notified WorkCover.