Mirarr Traditional Owners in the Northern Territory are disappointed at comments from Energy Resources Australia bosses they say undermine their cultural authority.

Criticism of the "disrespectful" comments in legal documents by ERA chief executive Brad Welsh and independent director Ken Wyatt comes as the company appeals the NT Government's rejection in July of a 10-year-extension to its minerals licence over the uranium-rich land surrounded by Kakadu National Park.

The pair claimed in legal documents the mining company was best placed to protect the Mirarr People's lands due to a veto-provision under the Long Term Care and Maintenance agreement.

Anti-Voice campaigner and former Indigenous Advisory Council chair Warren Mundine was also criticised for an opinion piece stating the economic benefits of nuclear fuel should be prioritised for the future benefit of the Mirarr people.

Mr Mundine, a non-executive director at two exploration start-ups focused on uranium, said "green-left activists" were "weaponising" cultural heritage laws. National Indigenous Times contacted him for further comment.

An ERA spokesman said the comments from Mr Welsh and Mr Wyatt were simply reiterating the company's position the legally binding veto over development "is the best arrangement to protect Jabiluka's cultural heritage".

The Mirarr people have long hoped to unite Jabiluka with the surrounding Kakadu National Park, a World Heritage Protected area, after celebrating Australia's longest-running uranium lease expiring earlier this month.

Despite a lengthy campaign by the Mirarr people to ban uranium mining in the Jabiluka area, ERA claimed in legal documents it was not aware Traditional Owners were so opposed to extending the 42-year lease.

ERA was granted access to the Jabiluka area – an undeveloped uranium deposit south of Ranger with an estimated 137,100 tonnes of uranium oxide – but was shocked when NT Mining minister Mark Monaghan a fortnight ago refused the extension, on advice from Federal resources minister Madeleine King.

The Rio Tinto subsidiary will challenge the decision in the Federal Court when a final, four-day hearing on the Jabiluka lease begins on October 28.

The NT government a fortnight ago declared a special reservation status over the Jabiluka mineral lease, the announcement coming exactly 27 years after the Mirarr people unfurled a giant 'Stop Jabiluka mine' banner and declared uranium mining would never happen on Country.

The Gundjeihmi Aboriginal Corporation, which represents the Mirarr Traditional Owners, as well as the Environment Centre NT and the Australian Conservation Foundation, all supported the NT Government's decision to not extend the licence and plans to reincorporate Jabiluka into Kakadu National Park, 300km east of Darwin.

The Ranger ore body, the richest in the southern hemisphere, was discovered in late 1969, with operation at the Ranger mine beginning in 1980, reaching full production of uranium oxide in 1981 and leading to the construction of the township of Jabiru in 1982.

Jabiluka holds profound cultural significance to its people, and both the mine and town are completely surrounded by Kakadu National Park.

ERA was its major employer but under current legal framework, was required to cease mining and processing activities on the Ranger Project Area by January 8, with final rehabilitation to be completed by January 2026.

ERA asked its biggest sharteholders, including Rio Tinto and Packer & Co, for $210 million capital to continue the rehabilitation at Ranger, warning it would run out of money by Christmas, as costs blew out from initial estimates of $808m to more than $2 billion.

The Jabiluka mineral lease has an estimated value of around $90 million.

An offer to buy the lease for $550m by Boss Energy was withdrawn after Federal environment minister Tanya Plibersek in July said the Albanese government intended to incorporate the site into Kakadu National Park, Mr Welsh said in an affidavit.

In its 2023 annual report, ERA said it didn't plan to develop the Jabiluka area into a uranium mine, saying it required approval of Mirarr Traditional Owners anyway.

Former federal environment minister and Midnight Oil frontman Peter Garrett had earlier called on the NT and federal governments to confirm they would give the area heritage protection.

"Now for the final step after decades of waiting," Garrett posted on social media site X before the NT government's announcement.

"C'wealth & NT please don't renew existing lease, instead commit to Jabiluka going into Kakadu National Park."