Prime Minister Tony Abbott is being urged to negotiate with East Timor to establish permanent maritime boundaries with Australia's northern neighbour, determining clear ownership of valuable oil and gas fields.
The Timor Sea Justice Campaign has called on Mr Abbott to show goodwill and draw a divide that gives East Timor fair ownership of resources close to its coastline.
"He needs to sit down in good faith with his Timorese counterpart and show that he's ready to talk about a permanent boundary," Campaign spokesman Tom Clarke said.
"No more of these temporary deals that simply short-change East Timor."
The campaign has been launched as the International Court of Justice (ICJ) hears arguments from both countries about Australia's alleged seizure of documents in 2004 during the formation of an oil and gas treaty that East Timor wants annulled.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The case continues.
An open letter to Mr Abbott from the Timor Sea Justice Campaign asks that an equitable boundary be determined in accordance with international law.
"Timor is not asking for charity, they are only asking for what they are legally entitled to, no more and no less," Mr Clarke said.
Without such a boundary East Timor would lose billions of dollars in oil and gas revenue, he said.
