The Metropolitan Crash Investigation unit is looking into the circumstances leading up to a crash at East Seaham which claimed the life of a 6-year-old boy.
A 29-year-old woman was driving a Mazda 3 on New Line Road just before 6pm on Sunday when she lost control and hit a power pole.
It's understood the boy, who was a rear seat passenger, died at the scene.
Police say a 3-year-old girl in the front passenger seat and the driver suffered facial lacerations and were taken to the John Hunter Hospital for treatment.
The woman has undergone mandatory blood and urine tests while at hospital.
