The government is considering a new tax on vapes as part of a drive to create a ‘smokefree generation’.
Documents published alongside the King’s Speech show the government will explore “a new duty on vapes as other countries have done”.
Ministers are understood to see vapes as a useful tool to cut smoking, but warn they are not risk free.
A new tax on vapes could target their affordability and therefore reduce their appeal.
No 10 said there was an "important balance" to be struck, to ensure there a significant difference between taxes on vapes and those on cigarettes, to prevent the move backfiring and encouraging people to take up smoking.
Around 40 countries around the world have taxed e-cigarettes, including Italy.
The government has also set out its plans to introduce tighter restrictions on vaping to protect children and phase out the sale of cigarettes.
The Tobacco and Vapes Bill will restrict the sale of tobacco so that anyone 14 or younger will never legally be sold cigarettes.
The King said the Government would introduce legislation to “create a smokefree generation by restricting the sale of tobacco ... and restricting the sale and marketing of e-cigarettes to children".
The move will effectively raise the age of tobacco sale by one year every year, the Government said.
According to government estimates, smoking costs the UK around £17bn a year, including £10bn every year through lost productivity alone.
This cost dwarfs the £10bn raised through taxes on tobacco products, its figures show.
Under the plans, smoking rates among those aged 14 to 30 could be near zero by 2040, calculations predict.
The King's speech also promised a "further crackdown on youth vaping" with a consultation currently ongoing on how to protect children while encouraging adult smokers to use vapes to quit.
It is asking for views on whether disposable vapes - known to be the first choice among children - should be banned or restricted and whether more needs to be done on pricing.
Health campaigners have repeatedly said that offering e-cigarettes for "pocket money prices" encourages children to take up vaping.
Other proposals include restricting the flavours and descriptions of vapes so they are no longer targeted at children, putting them out of the sight of young people and regulating packaging. Other suggestions in the consultation include on-the-spot fines for retailers who sell to underage children and greater measures to tackle online sales.
One in five children have now tried vaping despite it being illegal for under-18s, while the number of children using vapes has tripled in the past three years.
Richard Murray, chief executive of the King's Fund think-tank, welcomed the measures on smoking and vaping.
