Leader of the Welsh Liberal Democrats, Kirsty Williams will today co-host a debate against the ban on smoking e-cigarettes in public places that is being proposed by the Welsh Labour Government.
The anti-smoking organisation ASH Wales has also opposed the proposals.
When introducing the Government's white paper in April, the Health Minister said "There is no evidence of which I am aware that there is a second-hand smoke effect of e-cigarettes".
At the Welsh Liberal Democrat conference in Newport in April the party passed a motion calling for "an individual's free right to use electronic cigarettes where they like to be protected, unless there is evidence to suggest harm is being done to others."
Commenting, Kirsty Williams said:
"Thousands of people in Wales use e-cigarettes to cut down on the amount of tobacco they smoke, or quit altogether. According to the NHS, tobacco smoking is over 1000 times more toxic than e-cigarettes so we should not be driving people back to something far more harmful.
"I was very supportive of the smoking ban and believe that it has been tremendously successful. However, the Welsh Liberal Democrats believe in evidence based policy. Until evidence is produced that there could be a health risk to others, we will not support this ban".