Motorists across Northern Ireland are unlikely to see an in-car smoking ban before at least next May, the Cancer Focus charity claims.
It says the current administration has confirmed it will not hit its original deadline for the proposed ban before May 5's Assembly election.
The proposed legislation relates to people smoking when children are in the car, in a bid to reduce the damage caused by second-hand smoke. It would apply to any smokers in the vehicle, whether the driver or passenger.
Northern Ireland lags behind other parts of the British Isles.
Wales and England are introducing the sanction this October , the Republic of Ireland introduced the ban last year, while Scottish MPs are currently considering escalating their position.
Northern Ireland's efforts have been hampered through prioritising separate tobacco control steps, according to the cancer lobby organisation. But Stormont-based Irish assembly health officials believe an autumn deadline is still achievable.
Roisin Foster, chief executive of Northern Ireland's Cancer Focus calls it especially "disappointing" that the country's Executive looks likely to miss the chance to pass the law in its lifetime.
Other neighbouring countries' progress in pushing legislation through has magnified this disappointment, she added.
Simon Hamilton, Health Minister, says the hoped-for in-car smoking ban will not be passed by the current Assembly, according to Cancer Focus.
But The Department of Health, Social Services and Public Safety (DHSSPS) says the Health (Miscellaneous Provisions) Bill's draft is likely to be launched during October.
A department spokesperson says there is still time for the in-car smoking ban to feature in that Bill.
Safeguarding people, especially youngsters and children, from second-hand smoke's effects remains an important feature of the DHSSPS's 10-year plan for tobacco control, the spokesperson added.
Westminster is due to include Northern Ireland's cigarette outlets in part of plans to launch plain tobacco product packaging legislation in 2016.
Under the Westminster in-car smoking ban plans, drivers and passengers alike will be fined £50 if they are caught lighting up with minors aboard.
Copyright Press Association 2015