The Cancer Association of SA's lead researcher, Dr Carl Albrecht, yesterday said that more than 54% of tested sunscreen creams failed to protect people from the sun's UVA rays but his claim has been disputed by other medical experts.

Cansa recently tested 35 commonly available creams to check their effectiveness against UVA radiation, which is believed to cause a deadly form of skin cancer, melanoma.

But dermatologist Dr Rob Weiss said there was not sufficient evidence to suggest that sunscreens gave protection against melanoma but they were known to protect the wearer against other forms of cancer caused by over-exposure to the sun.

Dr Beverley Summers, of the Medunsa campus of the University of Limpopo, said the controversy around sunscreens was a "storm in a tea cup".

The photobiology laboratory, which she heads, tests many of the sun creams available in South Africa.

Summers, who is also an EUcertified cosmetics safety assessor, said some of the creams Cansa had tested failed the Colipa test, a new international standard for UVA assessment of sunscreens.

The full test protocol has not yet been fully implemented in South Africa.

It tests whether sunscreens break down chemically when exposed to UVA rays.

Summers said the creams that failed the test would be mildly less effective a few hours after being applied.

She said sun cream was usually less effective a few hours after being applied because people would touch their faces or bodies, wiping it off. It should be reapplied frequently.

She urged people to use creams made by reputable manufacturers.

"Use a reliable sunscreen and don't be put off by the current publicity," Summers said.