Electronic cigarettes offer a "huge potential public health prize" to Scotland, MSPs have been told.

Experts have recommended a cautious approach in regulating their sale and marketing, which will maximise potential benefits to smokers and minimise potential harm.

Concerns have been raised over the use of e-cigarettes - which allow users to inhale nicotine through a vapour - among children, and the lack of studies into their effect on the human body.

While some organisations, such as the Youth Commission, established by the Scottish Government, have called for a ban on all commercial sales of the products, others have urged a strong regulatory framework that protects children, while still allowing smokers to benefit from an alternative.

The Government is currently consulting on whether to ban sales to under-18s, make it illegal for an adult to buy e-cigarettes for someone under age, as well as restrictions on advertising and other regulatory changes.

Speaking at Holyrood's Health Committee, John Britton, director of the UK Centre for Tobacco and Alcohol Studies, said: "Electronic cigarettes offer a huge potential benefit to public health by helping smokers to shift to an alternative source of nicotine.

"If all smokers in Britain were to do that we would be talking of hundreds of thousands, if not millions of premature deaths avoided.

"So it is very important I think when legislating and controlling the inevitable abuses of the market that will come with electronic cigarettes, and the inherent risks within the products which we know relatively little about still...it is important to manage those risks, but not in a way that throws the baby out with the bath water, because there is a huge potential public health prize in these products."

Jeremy Mean, of the UK Government's department of health, said "a measured approach" was being taken south of the border.

"We can't be confident that the range of products is safe and therefore can't recommend their use to people. But we don't want to remove something that has potentially a great value if the regulatory framework is such that we can be confident that the products are of quality and will help people to cut down, to quit, and to reduce the harm of smoking."

Katherine Devlin, president of the industry body, the Electronic Cigarette Industry Trade Association (EU) Ltd, said: "We have to be enormously careful that we don't do more harm than good.

"The risk if we were to remove everything from the market, is we will see all those people who have made the switch to electronic cigarettes potentially returning to tobacco smoking."

Sheila Duffy, chief executive, of charity ASH Scotland, agreed that e-cigarettes could help smokers, but she said there were still many unknowns.

"We would love to see people who are addicted to tobacco being able to use these products instead of tobacco or to quit a tobacco addiction," Ms Duffy said.

"But there are so many unknowns, and I think the little evidence that we have supports both an optimistic but cautious approach. We believe that regulation needs to look at maximising the potential benefits and minimising the potential harm, and these products must work towards our vision for a generation free from tobacco in 2034."

Dr Andrew Thomson, of the British Medical Association in Scotland, highlighted concerns over the use of e-cigarettes by children, including primary school pupils.

Ms Devlin said the industry "absolutely support the mandating of an age-restriction".

She also admitted that full research into the health effects of e-cigarettes was needed, and that it had been "an error" that such work had not been carried out prior to the products going on sale.

"I totally agree that we need more research and we need to move faster on it," she said.