At least a dozen buses brought in after the road switch in Samoa last year are said by an expert to be illegal.
A veteran importer of motor vehicles, Bruce Mansell, says no motor vehicle should be older than 12 years.
But he says as an importer of buses from Japan for 30 years, he can tell the year of a bus by its colour scheme.
He claims at least a dozen he sees in Apia were older than 12 when they arrived in the country, and were allowed in by Customs.
Bus owners bought the buses not knowing the vehicles were older than they were told by the seller.
At least three bus owners discovered the true age of their right hand buses when they broke down and struggled to find parts because the year and other details they sent overseas suppliers of parts were wrong.