Only one fine has been issued for smoking in a car with children since the ban came into force just over a year ago.
The law was changed in October 2015, making it illegal to smoke inside a car with anyone under the age of 18 present to protect young people from the effects of second hand smoke.
The punishment for those found smoking in a car with children inside is a set £50 fine.
The news comes after freedom of information requests sent to all the police forces in England and Wales revealed that only one £50 fine was processed.
It has emerged that over the last year most cases where drivers have been caught smoking in a vehicle with children inside have only resulted in a verbal warning.
A spokesperson for the Department of Health said: “The measure of success for this legislation will be the changes in attitude and behaviour, not the number of enforcement actions.”
The fine for smoking in a vehicle with children present must be collected by the local authority after they have been notified by the police and have sent a penalty notice to the offender.
Police do not have the power to issue on-the-spot fines and have found it “really difficult” to enforce the law according to the South Wales Argus.