The Great Barrier Reef and Uluru are edging closer to the final round of a global contest to select the new Seven Wonders of the World.

The country's two most prominent landmarks are competing against 261 nominated sites from 222 participating countries around the world.

In stage two of the New7Wonders of Nature voting process, Uluru is in seventh place in its category and the Great Barrier Reef is in third.

Uluru in the Northern Territory is the world's biggest monolith, while the reef is the world's biggest coral reef comprising more than 3000 individual reef systems and beaches.

They are vying to be among the top 77 ranking nominees - 11 from each of seven categories - when voting in stage two closes next Tuesday.

A panel of experts in the New7Wonders of Nature campaign will announce 21 finalists on July 21 to proceed to the final stage of voting, which will conclude in mid-2011.

A Tourism Australia spokeswoman said the competition was tough, with Australia's nominees going up against the Grand Canyon, Ha Long Bay and Mt Everest.

"We have to get behind our Australian icons to make sure they are in with a chance," the spokeswoman said.

"Both the Great Barrier Reef and Uluru are equally worthy iconic natural wonders.

"With everyone's support they have a fantastic chance of reaching the ultimate seven.

"Winning a place in the top seven natural wonders of the world would be an amazing honour and a fantastic opportunity to further promote and preserve the complex balance of Australia's natural landscapes."

Tourism Australia has set up a web link to the voting site at www.australia.comhttp://www.australia.com/">www.australia.com;.

More than one billion votes are expected to be cast in the contest.

BRISBANE AAP