A new assessment also questions the effectiveness of e-cigarettes
The Health Information and Quality Authority (HIQA) says investing in ways to help people quit smoking is effective and offers good value for money.
The Health Technology Assessment (HTA), the first of its kind in the European Union, says pregnant women who smoke should be offered counselling in the first instance.
HIQA says there is "substantial evidence" to support the effectiveness of counselling for this section of the population.
It says other supports like health education and the use of financial incentives could significantly improve quit outcomes during pregnancy.
The HTA also found there is not enough evidence to "reliably demonstrate" that e-cigarettes can actually help people quit.
It has compared the cost-effectiveness of alternative mixes of ways to give up smoking.
Almost one-in-three people in Ireland use e-cigarettes in their attempt to quit smoking.
"HIQA advises the (health) minister to await the results of ongoing trials before deciding whether to recommend e-cigarettes.
"A decision to advocate e-cigarette use should take into consideration any additional information on the long-term safety of e-cigarettes use, and any emerging data in relation to concerns about the social normalisation of e-cigarettes leading to increased uptake among people who have never smoked, or later migration to tobacco cigarettes."
Smoking is seen as a major public health problem in Ireland, with one-in-five deaths each year due to tobacco smoke.
The amount spent per year on trying to quit smoking is estimated to be over €40m.
HIQA's director of Health Technology Assessment (HTA), Dr Máirín Ryan, said: "There are approximately 820,000 smokers in Ireland, with half making at least one quit attempt each year.
"This HTA has found that providing these interventions to help people quit smoking not only works, but is good value for money."
"Today's health technology assessment of smoking cessation interventions recommends using varenicline (either alone or in combination with nicotine replacement therapy [NRT]) for smokers wishing to use some type of pharmacological support in their attempt to quit."
Varenicline is a prescription-only medication, which helps people to stop smoking by reducing withdrawal symptoms and reducing the satisfaction that can be gained from smoking.
Nicotine replacement therapy (NRT) includes nicotine gum, patches, inhalers, intranasal and oral sprays and tablets.
Using varenicline alongside NRT is more than three and half times as effective as using no active medication, HIQA says.
However, it also says this is a relatively new combination of interventions - and any potential implications of widespread uptake need to be considered as part of the development of clinical practice guidelines and national health policy.
The report also found that behavioural interventions, like counselling and group behaviour therapy, are also effective in helping smokers to quit compared to quitting with minimal help.
But as pharmacological therapies are not acceptable to everyone, HIQA says it is important that behavioural ones continue to be provided.
The report found all interventions are effective at helping people quit smoking, and are cost-effective when compared with quitting without help.
The assessment has been presented as advice to Health Minister Simon Harris.