The Government Chief Whip is raising concerns about the implications and legal status of electronic cigarettes.
Last month the World Health Organisation advised against using the products - and said the risks they pose for the health of users has not been determined.
Minister of State Paul Kehoe has written to the Health Minister to clarify the health implications.
He said that according to the WHO there is no scientific proof that e-cigarettes help people quit smoking.
"People are not fully aware of what is contained in the electronic cigarettes and WHO have come out with some concerns regarding the electronic cigarettes," he said.
"They have stated that there is nothing there to show that these help people who are going off cigarettes and are on the wind down of cigarettes."