It may be more than a year before the public gets to see safety ratings for truck, bus and towing companies.
Data collected in the past two years by the Transport Agency for its new operator rating system has been used to give all heavy vehicle transport operators a provisional safety rating of between one and five stars.
The ratings have been determined from certificate of fitness inspections, roadside safety inspections and offences committed by drivers and operators.
The agency had initially planned to make ratings public by the end of this year, but access and use group manager Celia Patrick says because of industry disquiet about the system's accuracy, it could now be towards the end of 2013.
She says concerns have been raised about the quality and integrity of data being used.
Mrs Patrick says the agency is also looking at how to make the system more user-friendly for operators.
Of the operators, 95% have received a provisional rating of four or five stars and 2% one or two stars.