The Welsh Government could bring in legislation to make smoking in cars carrying children illegal if its new health campaign to crack down on cigarette use in vehicles fails.
The new campaign, which will last for three years, aims to deter smokers from lighting up in cars when youngsters are present.
First Minister Carwyn Jones said theWelsh Government would "consider" banning smoking while children are in the vehicle if the campaign does not succeed in having the desired impact by 2014.
Welcoming the latest move, Wales' chief medical officer said children exposed to passive smoking are at a higher risk of suffering from illnesses, such as asthma and respiratory infections.
Meanwhile, pro-smoking organisations said the Welsh Government's proposals would be "heavy handed".
However, Mr Jones said the Welsh Government aims to address inequalities in health, particularly the effects of tobacco on youngsters.
Copyright © Press Association 2011