E-cigarettes are a cost-effective way of helping people to quit smoking, the first official analysis of its kind in Europe has found.
Ireland is the only country in the EU to include e-cigarettes in a state assessment of how best to help citizens give up smoking.
Dublin's Health Information and Quality Authority (Hiqa) found that more people using e-cigarettes would lead to more people successfully kicking the habit.
It also said e-cigarettes are cost-effective and could save the public purse millions every year.
However, the health authority, which has yet to publish its final report after a public consultation, acknowledges long-term effects from the use of e-cigarettes have yet to be established.
It also says a more effective way of getting people to quit smoking is through the combined use of the nicotine addiction medication varenicline alongside nicotine gum, patches, inhalers or sprays.
But this would be more costly than the use of e-cigarettes.
Dr Mairin Ryan, Hiqa's director of health technology assessment, stressed the "high level of uncertainty" that remains around both the clinical and cost-effectiveness of e-cigarettes.
But she added: "Hiqa's analysis shows that increased uptake of e-cigarettes as an aid to quitting would increase the number of people who successfully quit compared with the existing situation in Ireland and would be cost-effective, provided that the currently available evidence on their effectiveness is confirmed by further studies."
The 700-page report found:
:: Varenicline was the most effective single medication for quitting smoking - more than two and a half times as effective as no drugs;
:: Varenicline alongside nicotine replacement therapy was more than three and a half times as effective as no medication;
:: E-cigarettes were twice as effective as no therapy (but this is based on only two trials with a relatively small number of participants).
Hiqa is putting its findings out for public consultation before it agrees on a final report, which will be put to Ireland's Health Minister Simon Harris.
Almost a third of Irish smokers use e-cigarettes as an aid to quitting smoking.
Ireland spends more than 40 million euro (£34 million) every year on helping people to give up the habit.
The Hiqa report says increasing the uptake of varenicline alongside nicotine replacement therapy would be "good value for money" but could add almost eight million euro (£6.8 million) to healthcare costs.
A rise in the use of e-cigarettes would cut the bill by 2.6 million euro (£2.2 million) every year, it found.