The Burrup Peninsula's possible status as a World Heritage site has been delayed by 12 months after the federal government's submission was deemed invalid.

The region in WA's Pilbara contains the world's largest and oldest collection of petroglyphs but UNESCO confirmed its nomination could not be considered until 2025, after the Australian government's submission was deemed incomplete, despite activist group Save Our Songlines claiming it was lodged before the February 1 deadline.

Known to Traditional Owners as Murujuga, the sacred rock art is considered the world's largest and oldest collection of petroglyphs, up to 40,000 years old.

Fuel giant Woodside is exploring the area for gas and wants to build a new LNG project that would produce billions of tonnes of carbon dioxide by 2070. It has pledged to avoid impact to cultural heritage during exploration and delivery of the project.

Mardudhunera woman and former chair of the Murujuga Aboriginal Corporation, Raelene Cooper, said the Burrup was currently a building site.

"Our sacred sites have been destroyed to make room for a massive fertiliser plant, with all its toxic emissions," she claimed.

A spokeswoman from Federal Environment minister Tanya Plibersek's office did not comment on the delay to the 2024 application, which was deemed incomplete because of issues relating to map boundaries and topography.

"Western methods of mapping don't allow for Indigenous understanding of cultural values, boundaries and knowledge," she said.

"The cultural landscape nomination spans across land and sea country, which is a difficult concept to fit into western concepts of borders."

Ms Pliberserk's office said an application for 2025 was now deemed valid and complete after the government and First Nations people worked with UNESCO to update its understanding of cultural boundaries.

"Further information on the progression of the nomination is a matter for the UNESCO World Heritage Centre," her spokeswoman told AAP.