The Federal Chamber of Automotive Industries (FCAI) has warned dangers to child safety could be enhanced in a car using counterfeit parts.
The FCAI partnered with Adelaide University's Centre for Automotive Research (CASR) to launch a program that tested the impact of frontal collisions with a child pedestrian at 40km per hour.
The Holden bonnet performed best across every test conducted with fake bonnets scoring the worst.
FCAI chief executive Tony Weber flagged the weight of counterfeit car bonnets as a major issue.
"The original equipment provided a better result in the event of an impact that could lead to traumatic brain injury.
"It was a small, but telling result. But I can say that as a parent, the safest result is the best one.
"The test was conducted at the same speed as the limit in many school zones and the weight of the head form device was calibrated to simulate the head of a child.
"I fear what would happen at a higher speed.
"The fake steel bonnet was twice as heavy as the genuine panel and that meant every time the steel bonnet was lifted it would crash down again after just a few seconds."
The CASR Impact Lab has conducted car crash tests since 2001.