East Timor's decision to take Australia to the international court over raids on its Canberra-based lawyer is a "big step" designed to ratchet up pressure over a disputed oil and gas treaty, one law expert says.
East Timor began proceedings in the International Court of Justice (ICJ) in The Hague on Tuesday over the seizure and detention of the documents by ASIO earlier this month.
The domestic spy organisation raided lawyer Bernard Collaery's office and seized documents relating to a dispute with Australia over a $40 billion oil and gas treaty.
Dili has accused Australia of bugging its cabinet office during 2004 negotiations on the treaty.
It is now seeking arbitration of that agreement, also at The Hague, and wants the deal renegotiated.
University of Western Sydney Professor of International Law, Steven Freeland, said while the ICJ action was a big step for East Timor to take, "the actions by Australia were ... fairly audacious".
"For one country to take another country to the ICJ alleging that the other country has breached international law, that's a big step, because you're essentially saying your friend and neighbour in this case has done absolutely the wrong thing," Prof Freeland told AAP.
"It clearly has diplomatic and political consequences, because the last thing Australia would want is allegations that they've breached international law."
He said the ICJ proceedings would provide East Timor leverage in negotiations over the Treaty on Certain Maritime Arrangements in the Timor Sea (CMATS).
"It ratchets up pressure on Australia, which I think from the East Timorese perspective is exactly what they want to do," he said. "I think it does embarrass Australia, and I think that's probably part of the negotiation tactics."
