the World Health Organisation (WHO) has called for a ban on the use of e-cigarettes indoors in public places.
In addition, the health agency said that sales to minors should be banned.
In a report on the regulation of e-cigarettes, it said that they are frequently marketed by manufacturers as aids to quitting smoking or as healthier alternatives to tobacco, and "require global regulation in the interest of public health".
The long-awaited report from the United Nations health agency will be debated by member states at a meeting in October in Moscow.
It said that regulations are needed to address health concerns like their indoor use.
"Legal steps should be taken to end e-cigarettes indoors in public and work places. Evidence suggests that exhaled e-cigarette aerosol increases the background air level of some toxicants, nicotine and particles," it said.
The WHO report also urged a range of "regulatory options", including a ban on e-cigarettes with fruit, candy-like and alcohol drink flavours until it can be proved that they are not attractive to children and teenagers.
The e-cigarettes have been marketed in almost 8,000 different flavours, and "there is a concern they will serve as a gateway to nicotine addiction and ultimately smoking, for young people", it said.
The report said that experimentation with e-cigarettes is increasing rapidly among teens.
Among the other conclusions was that there is "insufficient evidence" to conclude whether they help smokers quit or not.
"Therefore, WHO currently recommends that smokers should firstly be encouraged to quit smoking and nicotine addiction by using a combination of already-approved treatments," the report said.
Meanwhile, the Government is working on drafting legislation on "non-medicinal nicotine delivery systems" including e-cigarettes, according to the Department of Health.
However, there is currently no regulation of e-cigarettes in Ireland. Irish Rail has already banned them on services.
The drafting of the heads of a bill was approved by the Cabinet at the end of June, and the legislation would prohibit the sale of these products to minors here.