The British Medical Association has called on the government to ban smoking in public places in Northern Ireland.
Smoking has been banned in pubs in Ireland since March
Leading health professionals gathered in Belfast on Wednesday to put forward their case.
In the Republic of Ireland, the ban on smoking in the workplace came into being in March this year and has already had a significant impact.
It is expected smokers there will buy 500 million fewer cigarettes this year if the decline continues in the wake of the smoke free decision.
Deputy chairman of the British Medical Association's Board of Science, Newry doctor Peter Maguire, wants similar legislation introduced in Northern Ireland.
"What is good for the Civil Service is good for the rest of the workforce in Northern Ireland," he said.
"The Secretary of State for Northern Ireland must take action now.
"He has a responsibility to protect the health of people living in this country.
"Legislating to create smoke-free enclosed public places would be the single most effective law to improve health in this country."
Dr Fenton Howell of anti-smoking group ASH said the evidence was clear that smoke-free public places save lives.
"When they are in place, they are well respected and popular.
"As Ireland nears six months of being smoke-free, and Scotland looks poised to go the same way, I would urge the healthcare professionals and politicians here to lobby for the same protection for the people of Northern Ireland."
Dr Sinead Jones, director of the BMA's Tobacco Control Resource Centre, said no safe level of exposure to tobacco smoke had been identified.
"Ventilation is not a solution and non-smoking areas offer only partial protection," she said.
"Only smoke-free places protect health and government must act now to make all enclosed public places - including workplaces - smoke-free by law."
The anti-smoking campaigners presented their views to trades unions, the licensed trade and local politicians on Wednesday.
Cigarette market share
The BMA said it applauded the Irish Government's smoking ban in the workplace.
While the Northern Ireland Assembly was suspended, there was no reason why the secretary of state should not introduce legislation for the province on smoke-free public places through the Order in Council legislative procedure, it said.
Last week, a leading cigarette company revealed that its sales had fallen sharply in the Irish Republic since smoking was banned in workplaces.
Gallaher - which makes Silk Cut and Benson & Hedges cigarettes - had reported on Wednesday that sales in the UK had risen by more than 3% since April.
The group, which has about 50% of the Irish cigarette market share, said tax increases and the smoking ban had contributed to a 7.5% fall in the total cigarette market.
This means about 260 million fewer cigarettes were sold between January and June, and experts have forecast that if this trend continued, tax returns from tobacco would fall by 81m euros this year.