There are calls for barriers to be removed for those who want to quit
The Health Service Executive (HSE) says every week smoking causes 100 deaths and over 1,000 hospital admissions in Ireland.
Thursday is marking World No Tobacco Day, with a drive towards achieving a Tobacco Free Ireland by 2025.
It is hoped this will see less than 5% smoking prevalence here.
Research published shows that those most vulnerable in communities are most at risk of death and long-term smoking related illnesses.
It found that one in four men and one in five women still smoke, with smoking most common among young adults.
The HSE says children and young people who smoke experience poorer physical and mental health, with 'social' smoking and 'roll-your-own' emerging as challenges for tobacco control.
While over 1,000 people per day are supported by the HSE to quit smoking.
"With more quitters than smokers in Ireland, much progress has been made in reducing smoking prevalence in Ireland but we face new challenges as smoking prevalence has not reduced equally across the population," the HSE says.
The Minister of State with responsibility for Health Promotion, Catherine Byrne, says: "Each and every one of us, from across a wide range of organisations and state bodies, has a very important role to play in engaging with our communities to improve the health of our nation.
"We are all too familiar with the devastating effects that smoking has on our health; the stark reality is that tobacco related diseases are responsible for 6,000 deaths in Ireland every year.
"But the message is clear; these are preventable deaths. From the moment you stop smoking, you greatly reduce your risk of serious disease."
Dr Stephanie O'Keeffe, national director of Strategic Planning and Transformation at the HSE, says: "While we can see the achievements to date, with youth smoking having dropped from 28% in 2010 to 16% in 2017, new HSE research published today shows that smoking is now most common among young adults, suggesting that young people are starting smoking at a later age.
"Those young people who do smoke also experience poorer physical and mental health.
"It is up to each of us to work with the smokers we know and meet in our daily life, to encourage them to take the brave and best decision of their lives and quit for their own benefit, in terms of their quality of life".
Meanwhile the Irish Cancer Society is calling on the Government to make sure medical card holders do not face unnecessary barriers to accessing Nicotine Replacement Therapy (NRT).
Donal Buggy, head of services and advocacy at the Irish Cancer Society, says: "At the moment, people with medical cards need a prescription from their GP to get quit supports like NRT.
"This puts up an extra barrier for people who want to quit, and can place additional pressure on GP services."
Currently, people without medical cards can purchase NRT without prescription.
"This means that medical card holders, who are often from the most deprived areas and are twice as likely to smoke as those living in the most affluent ones, can find it difficult to get the support they need.
"We're calling for the Minister for Health to introduce legislation to make sure they no longer need to get a prescription for NRT," he says.
Information and advice on how to quit smoking can be found here