Two of the largest insurance companies in Ireland are reportedly refusing to cover cars that are 15 years old and older.
Aviva and Allianz will not insure the cars because they say they are more likely to be involved in collisions.
The restriction would affect around 250,000 car owners.
It will also apply even if the vehicle has an up-to-date NCT cert.
The decision comes despite official data suggesting that dangerous vehicles are linked to just a small fraction of all fatal and serious collisions.
Existing policy holders will not be affected but the Consumers Association says the move will restrict competition in the market.