File photo shows visitors looking at the 'Three Sisters' rock formation in the Blue Mountains, in New South Wales, Australia

Australia unveiled its newest national park, Everlasting Swamp, on Wednesday as thousands gathered in Sydney for the start of the once-in-a-decade World Parks Congress.

The week-long forum organised by the International Union for Conservation of Nature (IUCN) is set to lay out the global agenda for protected areas for the next 10 years.

"The hope of the is not bemoaning about the fate of nature, but rather looking at it as the provider of solutions, of human well-being," IUCN's Director-General Julia Marton-Lefevre told reporters.

She spoke as the New South Wales government announced that Everlasting Swamp, in the state's northern wetlands, is set to be its newest protected area. A portion of the new was already a state conservation zone.

The push to better manage some of the world's most biodiverse sites comes as part of a global effort to address the impact of climate change on the environment.

Marton-Lefevre said delegates in Sydney, including scientists and activists, would be developing a roadmap to meet a global 2020 target of protecting 17 percent of land and 10 percent of marine areas.

About 15 percent of the world's land mass and three percent of its marine areas—more than 200,000 sites around the globe—are currently designated as protected areas.

Host nation Australia said it had already met its 17 percent land conservation target, which Environment Minister Greg Hunt described as a "downpayment to the future".

The Yosemite National Park in the United States. About 15 percent of the world's land mass and three percent of its marine areas—more than 200,000 sites around the globe—are currently designated as protected areas

"This congress is about protecting the great forests, and the ocean and the savannah lands, not just for 30 or 50 years but for 100 years," Hunt said.

"It is about the gift we give to our grandchildren and their grandchildren. And it is a congress focused on realistic hope that we have made progress, but that we can do better and we can make commitments that will last... for centuries."

The World Parks Congress, which officially opens later on Wednesday, involves more than 5,000 people, including five heads of state and 30 environment ministers.