The United Nations' highest court on Monday banned Australia from making any use of documents it seized from a lawyer working for East Timor in an arbitration case over a multibillion-dollar oil and gas deal between the two nations.

The International Court of Justice also ordered Canberra not to "interfere in any way in communications" between East Timor and its legal advisers in the arbitration or future negotiations on a maritime boundary between resources-rich Australia and its tiny, impoverished northern neighbor.

Australian agents in December raided the Canberra office of a legal adviser to East Timor and seized documents and data. That followed claims by a former Australian spy that his country bugged the East Timorese government ahead of negotiations on the Timor Sea Treaty that carves up revenue from oil and gas under the sea between the two countries.

East Timor wants to renegotiate the treaty, arguing that it is invalid because of the alleged bugging.

It went to the world court arguing the seizure was illegal. Monday's orders did not address that claim, which will be litigated later.