The smoke ban in Wales has led to a 20% increase in people wanting to quit the habit, according to Stop Smoking Wales.
The smoking ban came into force on 2 April in Wales and chief medical officer Tony Jewell said it had had a positive impact on health.
Figures show 25,000 have contacted Stop Smoking Wales since 2004 for advice on how to quit.
"While the number of adult smokers is falling, there are still 6,000 premature deaths each year due to smoking," Jewell told the BBC.
"A quarter of adults in Wales still smoke - more than the UK average - and children are taking up the habit around the age of 12.
"In particular, I'd urge those who expose children to second-hand smoke to give up.
"More mothers-to-be smoke in Wales than in any other part of the UK, and over a third of households with children still contain a smoker."
He said smoking prevalence in Wales had fallen from 35% in 1978 to 25% in 2007 but believed the figure could be even lower.
"We should be aiming for an intermediate goal of 17% prevalence, as has already been achieved in Sweden and California."