A proposed new standard that would allow the sale of factor 50+ sunscreen in Australia has come under fire, with claims it has more to do with pushing new products than protecting people from skin cancer.

Australians suffer more than anyone else from skin cancer and Standards Australia says the move would offer the best possible protection to consumers, who can currently only buy SPF30+ sunscreen.

It sounds like a big improvement, but Professor Ian Olver from the Cancer Council says SPF50+ does not really offer much more protection than sunscreens that are currently on the market.

"It's really only 3 or 4 per cent," he said.

"It's more important that we look at whether sunscreens are broad spectrum, and insist that people reapply them regularly, than the difference between 30 and 50."

SPF is a measure of how much solar energy is required to produce sunburn on protected skin compared with unprotected skin.

Professor Olver says SPF30+ is enough, and it is actually more important for consumers to check if their sunscreen blocks both types of UV rays.

"In terms of standards, the fact that the sunscreen blocks both UVA and UVB light is probably more important than the small gain you'd get between 30 and 50," he said.

The new standards will also ban terms such as sunblock and water proof, because they may be misleading.

Professor Olver says that is a good idea because the terms may lull people into a false sense of security.

But he is concerned that putting SPF50+ on the market may have the same effect, and people may be more negligent about re-applying their sunscreen, in the mistaken belief that they will not need to.

He says the new standard appears to be more about selling sunscreen than stopping sunburn.

"There may be a marketing advantage, you see, to being able to advertise a sunscreen with what sounds like a far higher protection factor," he said.

Colin Blair, the head of Standards Australia, says the change is needed because people routinely underestimate the amount of sunscreen they need.

"They're not putting on the correct amounts. At 30 you're obviously getting more exposure, but if you're not putting on the correct amounts, at 50 at least you're getting a, you know, an increased protection than you would be if you're not putting on the incorrect amounts at SPF30," he said.

The Cancer Council says they have concerns about this because it might lull people into a false sense of security. In other words, they will not reapply.

"That's one of the reasons you'll find in the standard that we've said we don't want to see the words sunblock or waterproof products because I think they're the ones that are lulling people into a false sense of security," he said.