Adverts that encourage children to try electronic cigarettes should be banned, council leaders have said.
The Local Government Association (LGA), which represents almost 400 councils in England and Wales, said firms are exploiting the "haziness" around the marketing of e-cigarettes and warned they could become a "gateway" to children smoking normal cigarettes.
While it recognised that e-cigarettes have public health benefits in helping smokers quit, it said the rules around marketing need tightening.
Otherwise, the current situation threatens to "undermine" efforts to tackle smoking among children and young people.
The call comes after Cancer Research UK warned that children must be protected from the "unregulated marketing" of e-cigarettes.
Its research in November of 1,000 pieces of marketing found brands were using social media, apps on mobile phones and group discount vouchers for e-cigarettes.
Innovative packaging and flavours such as strawberry, apple and cherry also appeal to young people, the charity said
Katie Hall, chair of the LGA's community wellbeing board, said: "It is totally unacceptable for e-cigarette advertisers to target children.
"We cannot allow these devices to become a first step to long-term regular smoking for a generation of youngsters.
"Manufacturers of e-cigarettes have repeatedly claimed they don't market to kids but their actions tell a vastly different story.
"They are using the same sophisticated tactics long employed to sell regular cigarettes. These involve sweet flavours, social media, celebrity and competitions."
The Committee of Advertising Practice has launched a public consultation on proposals to introduce new rules for the advertising of e-cigarettes.
Ms Hall said: "Responsibly marketed and properly regulated, e-cigarettes and other nicotine delivery systems can benefit public health by helping smokers to quit.
"They can significantly reduce the number of people who use conventional cigarettes and die of tobacco-related disease.
"However, if they continue to be irresponsibly marketed, they could make regular cigarettes look glamorous again and undermine decades of hard work to reduce youth smoking.
"We welcome news that advertising watchdogs have launched a public consultation and we hope it results in tough and immediate action."