The NSW government says an external investigation is underway after the remains of the oldest humans ever discovered in Australia were buried in defiance of a legal challenge.
The 42,000-year-old skeletal remains of Mungo Man and Mungo Lady were removed from a secure facility last week.
It is believed they were buried in an unknown location within the Willandra Lakes World Heritage area, in the state's south-west.
A spokesperson from Heritage NSW said the NSW government "did not authorise, conduct or endorse the removal and subsequent reburial of any remains on 24 May" and an external investigation into the removal of the remains and their reburial was now underway.
The final resting place of Mungo Man, Mungo Lady and 106 other Indigenous ancestors, which were removed in the 1960s and 1970s without the permission of traditional owners, has been the subject of debate for decades and caused division within the three Aboriginal groups linked to the area.
The Willandra Lakes Aboriginal Advisory Group, an elected consulting group of nine traditional owners, was in favour of the reburial plans, which were approved by former federal environment minister Sussan Ley in April.
But some traditional owners opposed the plans.
A separate group representing the area's three Indigenous groups, the Mutthi Mutthi, Ngiyampaa, and Barkandji-Paakantyi, last week filed an injunction to prevent the burial under section nine of the Aboriginal and Torres Strait Islander Heritage Protection Act 1984.
The group had been "outraged" by the burial and called for an independent investigation.
They say they've now taken emergency legal action to ensure the ancestral remains are protected from further degradation.
Mutthi Mutthi man Jason Kelly, one of the six applicants seeking urgent action by the incoming federal environment minister, said elders were extremely concerned the remains were still unsafe.
"Assurances by the NSW government that Mungo Man and Mungo Lady would be safe and secure were found to be plain wrong," he said.
"What's now apparent is that the most significant cultural ancestral remains in Australia, and globally, had less security than most suburban homes."
They're calling on both state and federal governments to help implement a three-phase plan in line with their aspirations, including culturally-appropriate burials, in a secure manner, at a known location with a marking or simple memorial.
Last week, the federal Department of Agriculture, Water, and Environment said it was advised the remains had been buried despite an "expectation, based on communication with the NSW government, the reburial would not be occurring", and would be delayed until the incoming federal minister had assessed the application.
A new federal environment minister is yet to be announced by the Labor government, but incoming Minister for Indigenous Australians Linda Burney told the ABC last week the Commonwealth was seeking an explanation from the state government.
"We have just written to the NSW department asking them for very pointed details about what actually took place," she said.
The state government said the remains of the other 106 ancestors were being stored in a facility under a new security arrangement.
