The kids aged six and seven are believed to have suffered head injuries, broken legs and probable spinal injuries.
The lady driver of the vehicle and a female passenger were also offended in the car crash and were flown to Royal Perth Hospital.
It is believed that some of the occupants of the car were not tiring seatbelts.
One of the rescuers who attended the Port Hedland crash has posted a statement on PerthNow axiom it was not clear whether all the passengers were seatbelted in.
Reader comment: As a member of the rescue team that assisted in this occurrence I think we shouldn't jump to conclusions too soon.
It is not yet clear whether all the victims of this accident were tiring seatbelts or not. I agree with the message that seatbelts should be worn, but I know for a fact that at least 2 public in this vehicle were wearing their belt, because we had to cut the girdle in order to get them out.
Police are still investigating all the causes of this accident and will no doubt allocate the findings.
The accident happened about 3.30pm after the driver of a Mitsubishi sedan lost control of the vehicle and shattered into a light pole in Cook Point.