The British health regulatory agency has revealed that it will be classifying electronic cigarettes, which have emerged as popular substitutes for those who want to quit smoking, as medicines.
The MHRA health products watchdog said their proposals would help reassure customers about the quality of e-cigarettes, currently used by about 1.3 million people in Britain.
The government is backing plans for a European Union-wide law, which could come into effect by 2016 and would require e-cigarettes to have a medical licence, officials said.
Until then, the MHRA is encouraging manufacturers to apply for a licence, which would signal to customers that their products are safe and effective in the amount of nicotine they dispense.
E-cigarettes contain a liquid, usually made up of propylene glycol, nicotine and flavourings, which is heated up and delivered as a gas to the lungs with each draw.
The user exhales vapour, but not smoke, a practice called "vaping."
"Reducing the harms of smoking to smokers and those around them is a key government health priority," said Jeremy Mean, group manager of vigilance and risk management of medicines at the MHRA.
"Our research has shown that existing electronic cigarettes and other nicotine-containing products on the market are not good enough to meet this public health priority."
He said the government would seek to license all nicotine-replacement products, including gums, patches and mouth sprays, to ensure customers are provided with quality products.
"It's not about banning products that some people find useful, it's about making sure that smokers have an effective alternative that they can rely on to meet their needs," he said.
The benefits of e-cigarettes are that they provide a nicotine hit and the sensation of smoking without the tar, ash and toxins found in conventional cigarettes.
But the UN's World Health Organisation (WHO) has said that the safety of e-cigarettes "has not been scientifically demonstrated... (and) the potential risks they pose for the health of users remains undetermined."
Britain's approach differs from that of France, which last month announced restrictions on the sale, use and advertising of e-cigarettes that put them in the same bracket as tobacco.