While alternatives to conventional cigarettes, such as vapourisers, are often touted as being less harmful to health, experts said they come with their own cocktail of toxins.
The importation, distribution and sale of vapourisers, including e-cigarettes, e-pipes and e-cigars, are illegal under the law. Vapourisers are devices that heat up a liquid that usually contains nicotine, and turn it into vapour inhaled by the user.
"E-cigarettes contain substantially less harmful chemicals than conventional cigarettes. (But) increasingly, there are reports that they contain various toxins which can harm the lungs and other organs," said Dr See Kay Choong of the National University Hospital.
A 2014 World Health Organisation report said the amount of nicotine consumed by the user "varies widely, ranging from very low to levels similar to that of cigarettes, depending on product characteristics, user puffing behaviour and nicotine solution concentration".
But a 2015 report by Public Health England estimated e-cigarettes to be 95 per cent less harmful than cigarettes, and said they could be used to help smokers quit.
That report was met with some scepticism. A Ministry of Health response to the media then said e-cigarette vapour still contained cancer-causing agents.
Dr See said the use of e-cigarettes in other countries has shown mixed results. Some smokers have been able to make the switch from tobacco smoking, while using e-cigarettes has ironically led some non-smokers to pick up the habit of smoking conventional cigarettes.
Dr Loke Wai Chiong, Deloitte's South-east Asia healthcare sector leader, said products like e-cigarettes "provide the nicotine fix without the harmful effects of tar", but nicotine's addictive effects can still result in problems like adverse behaviour when in withdrawal.