It comes as the Republic of Ireland plan to ban the use of them in hospitals next month.The government of NI is not following suit - but Andrew Dougal from Chest Heart and Stroke said he believes there is a lot of confusion over the use of e-cigarettes which needs to be cleared up."We are calling for a ban on the use of e-cigarettes in all public places," he told UTV."It is important we have compliance with the smoking ban in public places and with these devices causing so much smoke it's making it difficult for people to implement the smoking ban."Smoking was banned in NI seven years ago and e-cigarettes are the latest product on the market designed to help people quit the habit.The cost of using them is 75% cheaper but opinion on using them in public places remains divided.A statement from the Department of Health said it has no plans to enforce a ban - but said individual trusts could do so under their own health and safety workplace policies.It explained: "The Department has no plans at present to introduce legislation banning the use of e-cigarettes in HSC premises in Northern Ireland. "However, individual Trusts may introduce bans on the use of e-cigarettes on premises under their own health and safety workplace policies if they so wish, in a similar way as the Western Trust introduced a complete ban on smoking on Trust grounds in March 2014."