French Polynesia's accounts office says it has failed to establish how many government vehicles there are but guesses their number at about 1,000.
In its report it says the fleet is poorly managed as it is made up of 36 car makes.
It also said the fleet is old and inefficient, with less than half of the cars in good working order.
A report in 2013 found that the cars have high emissions because most of them are diesel-powered.
And figures from 2016 suggested that the administration couldn't account for about a quarter of the vehicles.
It recommends the government establish a management structure and budget for a renewal of the fleet.