THE Northern Land Council has refuted a lawyer's claim to have unearthed new evidence in the Muckaty Station ownership battle.

The site - near Tennant Creek - is at the centre of a major dispute between Aboriginal families over who has the right to allow the establishment of a nuclear waste dump.

A group of Yapa Yapa elders last year took Federal Court action to stop the plans. They are represented, pro-bono, by Melbourne law firm Maurice Blackburn.

The case has been stalled for mediation and will return to court in September.

Solicitor Martin Hyde said his clients had legitimate claim to ownership.

"They therefore have the right to refuse the radioactive waste establishment," he told the NT News.

But, the NLC says under traditional law the Lauder family, of the Ngapa clan, have sole claim to the area known as Muckaty Station.

The family has given the project a green light, and stands to gain $12 million.

Mr Hyde said it was a "disgrace".

"Now, National Archive documents ... show the Northern Land Council did not correctly identify and obtain consent from the traditional owners of the land," Mr Hyde said. The information was on the public record after being tendered to Aboriginal Land Commissioner Justice Peter Gray.

But Mr Hyde said: "It was buried by the NLC.

"The Muckaty Land Claim documents obtained from the National Archives show the nominated site is not exclusively owned by the Lauder family," he said.

"Also, according to the NLC's own expert, anthropological evidence tendered in the Muckaty Land Claim, all Ngapa land on Muckaty Station is owned in common by three subgroups. This raises serious questions in light of the information contained in these documents".

But CEO Kim Hill said the claims were misplaced: "All information before the Aboriginal Land Commissioner, and findings in the land claim, were considered by the NLC when nominating the site in 2007."