SYDNEY, Sunday 6 June 2010 (AFP) - Goggles and snorkels were the only compulsory items when brave swimmers stripped off Sunday for a nude snorkel designed to raise awareness about Australia's Great Barrier Reef.

The event at Nelly Bay Beach on Magnetic Island, off Australia's northeast coast, drew 23 snorkellers and 10 swimmers aged between 19 and 60 for the 20-minute splash, organiser Ben Schultz said.

"We had blue skies and the water was not chilly at all," Schultz told Australian news agency AAP. "It was like a bath."

The event, to mark the United Nations World Oceans Day on June 8, drew an estimated 250 spectators.

"No, they weren't there for a perv (a lascivious look) but to show their support for the environment," Schultz said.

Fears of an environmental disaster on the Great Barrier Reef, which is home to scores of marine species, were heightened earlier this year when a Chinese coal carrier ran aground on the massive coral reef.

The boat was later removed without a serious oil or coal spill but it gouged a huge scar in the world heritage-listed coral.