The CC commissioned MSX International to look at quality of repairs carried out on vehicles involved in accidents as part of its investigation.
Head of the NAB Frank Harvey, said: “NAB believe that a much larger sample of post repair inspections need to be analysed so further and more definite conclusions can be reached.
“We also believe that it is critical that written off vehicles that have subsequently been returned to the roads should be included within any further post-repair inspection sampling.
“We urge the Competition Commission to facilitate a meeting of interested parties to discuss the report’s findings. In particular to understand the technical output relating to repair methods and to better understand the wider commercial dynamics that may be driving incorrect behaviours including an examination of insurers’ approved repairer contracts and selection criteria.
The investigation saw 104 vehicles inspected between June and October, with 77 cars being repaired by the at-fault insurer and 27 by the non-fault insurer.