The Children's Commissioner, Judge Andrew Becroft, is demanding MPs stop stalling and ban smoking in cars carrying children.
In 2014, the Health Select Committee was presented with a 2000-strong petition calling for a ban on smoking in cars with children under the age of 18.
The petition received cross-party support from the committee, which was comprised of MP's from Labour, National, the Greens and New Zealand First.
But four years on, Judge Becroft said progress had stalled, and it was time to take action.
"If children had a voice, and if they were asked, and if they could vote, knowing what we do about the dangers of smoking, I bet I know what children would say," he said.
"As Children's Commissioner I'm saying it for them.
"Ban it. Stop it. Move on it."
Judge Becroft said it was simply about protecting children from the life-threatening dangers of second-hand smoke.
"We seem to be beset by technicalities and possible objections by the police, who see it as 'difficult to enforce'," he said.
"So we are in the position where we are ready to go, and no one can give a good and compelling reason why we shouldn't, but yet we've stalled- and we've stalled for too long."
Figures from the Smokefree New Zealand website indicate 16 percent of adults smoke in New Zealand and it is estimated more than 100,000 children are exposed to second-hand smoke in cars each week.
Otago University Public Health Professor Richard Edwards said children must be protected from second-hand smoke.
"The whole reason that we introduced smokefree workplaces was to protect people in the workplace from an exposure to a health hazard that was involuntary because it was in their workplace," he said.
"So children are being exposed in exactly the same way but they don't have the same protection."
In a statement, Associate Minister of Health Jenny Salesa said regulations regarding smoking in cars were still being considered.
"For this reason there is promotional work around smokefree cars currently underway through the Health Promotion Agency, particularly for Māori and Pacific communities," she said.
"However, our current focus around smoking regulations has been on vaping. This week I will be meeting with the Children's Commissioner Judge Andrew Becroft to discuss smoking in cars with children present."