DOCUMENTS unearthed in the National Archives challenge the Gillard government's push to build a nuclear waste dump on disputed Aboriginal land near Tennant Creek, lawyers say.

Martin Hyde, a senior associate of the law firm Maurice Blackburn, says the discovery of documents showing that one Aboriginal family group does not exclusively own the land raises serious questions about the nomination of the site by the Northern Land Council.

Opposition... protestors block a bridge near the proposed Muckaty waste site, which is close to Tennant Creek. Credit:Angela Wylie

''This is vital information for the case,'' said Mr Hyde.

Traditional owners have begun a challenge to the nomination in the Federal Court.