Driving off-road vehicles over Australia's beaches has a devastating impact on a hidden ecosystem of tiny animals that live among the grains of sand, new research shows.

While driving 4WD cars on sand is a popular pastime, Associate Professor Thomas Schlacher from the University of the Sunshine Coast at Maroochydore says it has unrecognised environmental consequences.

"Most people go to the beach and don't realise there's actually a lot of life there," he says.

"If you take a handful of sand you can find dozens of species. The beaches are a habitat full of life."

The creatures that make their homes in the sand include tiny sea-snails, shrimp and other animals. Many of them are so small they can essentially tunnel between the sand grains.

In the traffic-affected beaches, the number and variety of tiny animals was dramatically reduced, they found.