People in Wales could face a £50 on-the-spot fine if they are caught flouting a ban on smoking in cars carrying children.
The move, part of new plans from the Welsh Government which will come into force in 2015, is designed to protect the health of children and young people from the harm associated with exposure to second-hand smoke when travelling in private vehicles.
It would be an offence to smoke in a private vehicle when children under the age of 18 are present, under the proposed changes to the law,
The Welsh Government explained that enforcement of the new law will largely be taken forward by police officers in conjunction with their wider functions on road safety.
"Children and young people have the right to breathe clean air and enjoy smoke-free environments," said first minister Carwyn Jones.
"Protecting children from exposure to second-hand smoke will help give them the best start in life.
"Some people light up in their cars without thinking and believe that opening the window will help disperse the smoke; however it simply blows back into the car.
"Children cannot escape from the toxic chemicals contained in second-hand smoke when travelling in vehicles."
Ministers are also consulting about whether the Welsh Government should legislate in the future to prohibit the use of e-cigarettes in private vehicles carrying children under 18.
Smoking continues to be the largest single preventable cause of ill health and premature death in Wales, causing around 5,450 deaths in Wales in 2010, according to official figures.
A six week consultation on the ban is being launched on 11 September.