The new Miss Earth Australia has donned a Paul McCann masterpiece as her national costume to represent Australia for 2022.

Sheridan Mortlock took the crown in September and is advocating for "action, care and education" around climate action for the future.

On the weekend Mortlock announced her national costume for the competition as a gown from Marrithiyel and Deley artist and designer Paul McCann's newest collection.

Titled Silver Lining, McCann's new collection pays respect to his grandparents and their time in the 1950s. McCann's new collection recently saw its glitterati debut at Melbourne Fashion Week, where it brought on a standing ovation as it closed the Ganbu Marra runway show.

In her advocacy for climate justice, Mortlock said it was important to acknowledge the work First Nations people have done in caring for Country.

"As a white Australian representing my nation, I wanted to showcase the talents of our Indigenous artists on an international stage," she said.

"The relationship to Caring for Country maintains a wealth of knowledge of our ecological systems invaluable to the development of our collective understanding to the historical underpinnings of the current phase of climate change.

"It's no surprise that the most ecologically intact parts of Australia are Aboriginal owned."

The gown worn by Mortlock was inspired by the downpour of rain and lighting onto Australia's dry earth and how it feeds the soil and breathes life.

Mortlock also called for the nation to better recognise First Nations people.

"As a nation it is long overdue for Australia to recognise and make space for our First Nations people," she said.

"The Silver Linings silhouette plays on the idea of Indigenous Australians seeking sovereignty and a Treaty to give a voice to and make space for Indigenous Australians."

Miss Earth will be crowned on November 29 in the Philippines.