"The harm outweighs the benefits - and so advertising, marketing, sponsorship, and sales of e-cigarettes should come with a warning and be regulated as rigorously as cigarettes,” preventative medicine specialist and anti-smoking activist Manfred Neuberger said.
The tobacco industry makes over $3 billion annually (€2.4 billion) from the sale of e-cigarettes.
"There are scientific studies that show that the vapour inhaled with e-cigarettes contains a similar number and size of particles to that of cigarettes. On top of this, all the ingredients are not always declared, and it can be hard to control the dose," Neuberger said.
He added that solvents and other additives in e-cigarettes (such as propylene glycol and ethylene glycol) could also cause lung damage.
Currently there is very little data about the long term effects of e-cigarettes, and people can still get hooked on nicotine through vaping.
However, researchers from University College London recently said that warnings over e-cigarettes are alarmist - and increasing their use could save many lives.
For every million smokers who switch to e-cigarettes, more than 6,000 lives a year could be saved, according to the UCL team.
They argued that even though some toxins were present in vapour from e-cigarettes the concentrations were very low.
Last month the World Health Organization called for e-cigarette use to be banned in public places and workplaces. The WHO said this was because they could increase the levels of some toxins and nicotine in the air.