Vapour from e-cigarettes could harm lung cells and the effects could be similar to those seen in cigarette smokers, according to a new study.

E-cigarettes are devices that heat a cartridge of liquid nicotine into a vapor. It is widely agreed they are likely to be less harmful than smoking cigarettes and are often used as an aid to quit smoking.

Research led by the University of Birmingham and published in the journal Thorax shows that vaporised e-liquid disables key protective cells in the lungs.

These protective cells, called alveolar macrophages, engulf and remove dust, bacteria, and allergens that have entered the lungs.

This does not mean e-cigarettes are as dangerous as cigarettes, but it suggests e-cigarettes may be more harmful than we think.

Co-author Professor David Thickett said further studies were needed.

"It has been suggested electronic cigarettes are safer than traditional cigarettes, and this narrative is increasingly supported by tobacco companies that have established research institutes devoted to generating supportive data," he said.

"E-cigarette users have been given advice based on relatively little information.

"We hope that by disseminating this data as widely as possible the public can at least make an informed choice; the public must be aware these devices are not harmless."

Vaping could damage vital immune system cells: Researchers

In the study, researchers extracted alveolar macrophage cells from lung tissue. They exposed a third of these to plain e-cigarette fluid, a third to different strengths of the artificially vaped condensate with and without nicotine, and a third were exposed to nothing for 24 hours.

The results showed that the condensate was significantly more harmful to the cells than e-cigarette fluid and that these effects worsened as the 'dose' increased.

Exposure to the condensate increased cell death and boosted production of oxygen free radicals 50-fold and significantly increased the production of inflammatory chemicals.

The commercial supply of nicotine for use in e-cigarettes remained prohibited in Australia under state and territory legislation.

In October last year, Health Minister Greg Hunt said he would never lift the ban on e-cigarettes despite an ongoing Senate inquiry into their use.

In March this year, that inquiry recommended the National Health and Medical Council fund an independent review of the available evidence of the health impacts of vaping and e-cigarette liquids, as well as a review of the regulations around the world.