In a provocative presentation to a Melbourne conference this week, Martin Feelisch, a professor of clinical and experimental sciences at the University of Southampton, questioned whether it was time for a "radical rethink" of the advice given to people about how much time they should spend in the sun.

Professor Feelisch said recent epidemiological studies suggested that the health benefits of moderate sunlight exposure outweighed the harmful effects of UV radiation on the skin.

In particular, a recent study conducted with colleagues at the University of Edinburgh found that a dose of UV equivalent to about 30 minutes of sunshine during the summer in southern Europe lowered people's blood pressure.

The research, published in the Journal of Investigative Dermatology, suggested UV radiation triggered natural stores of nitric oxide in the skin which dilate small blood vessels. The mechanism was independent of Vitamin D in sunlight which is already known to improve bone and muscle health. This means it cannot be substituted with a vitamin D supplement.

Several other studies have also shown that people with mild hypertension tend to have lower blood pressure in summer compared to winter, and that the further you live from the equator, the more likely you are to suffer from high blood pressure and heart disease.

Professor Feelisch said given high blood pressure was a major risk factor for heart disease and stroke, which accounts for 30 per cent of deaths globally each year, health authorities should start focusing more on the benefits of sensible sun exposure.

"We have to balance the benefits with the detrimental effects for the greater good of the entire population. The current public health advice is dominated by concerns about cancer," he said.

"That may be very important for a high risk group but that high risk group are the minority of the population. Many others would probably very likely tolerate higher than currently recommended exposure levels, provided their skin gets gradually used to this, and their health would benefit from that."

Professor Feelisch said it was possible that public health campaigns, such as the "Dark side of tanning" television advertisements which have been running in Victoria for five years, were scaring people into hiding from the sun.

"Everybody is so scared to expose themselves to natural sunlight or slap on sunblock lavishly even if they go outside for 15 minutes," he said at the Australian Health and Medical Research Congress. "That is cutting precisely the bit that is required to keep us healthy."

But head of the Australian Cancer Council Professor Ian Olver said current public health advice was sophisticated in Australia, balancing the pros and cons of sunlight for Vitamin D and emphasising high UV index times when people are more likely to burn.

"If the UV index is three or above, the sun is intense enough to burn you and therefore you need to take some protection measures. If it's less than three, you can probably safely go out in the sun. So for vitamin D, early in the morning or late in the afternoon, it might be fine to go out without protection but in the middle of the day, it usually isn't."

Professor Olver said despite these campaigns, Australia still had high rates of skin cancer. There were still more than 12,000 melanomas and 430,000 non-melanoma skin cancers diagnosed each year and about 2000 people died from the disease annually, he said.