Former East Timor leader Xanana Gusmao is a softly-spoken man, but is firm when it comes to talking about Australian prime ministers, past and present.

After starting out as a resistance commander against Indonesia, Gusmao became the first president of the independent Timor-Leste and then served as prime minister for about eight years until 2015.

He is now the chief negotiator in Timor’s David-and-Goliath struggle to negotiate a maritime boundary with its far bigger neighbour, Australia, which includes rights to the oil under the seabed.

• Legal battle with East Timor over
• Nepal, Baltimore, Bali: spectacular pictures
• Kidman deal ‘contrary to national interest’

Speaking to The New Daily during a visit to Melbourne, Gusmao ran through the various machinations between Timor, Australia and Indonesia over maritime boundaries and oil over the last half-century.

Gusmao concedes that Timor again showed its inexperience in signing the 2006 Treaty on Certain Maritime Arrangements in the Timor Sea (CMATS).

The tiny nation argues that international law supports the maritime border being on the median line between it and Australia, which would put contested oil and gas reserves in Timorese waters.

As things stand, Timor gets 90 per cent of the output in a Joint Petroleum Development Area and there is a proposed 50-50 split of Woodside Petroleum’s undeveloped Greater Sunrise field.

When Gusmao was prime minister, he put the Timorese case to his counterpart Julia Gillard, who insisted Australia had done no wrong.

“In the time of Julia Gillard, I tried then to tell her we’ve got a problem and better to talk. We don’t want to blow up all of these issues, but she didn’t listen to me.”

Talks riddled with complexities

In 2013, Timor launched confidential proceedings in the Permanent Court of Arbitration, arguing the treaties that divide the petroleum revenue are invalid because Australia bugged the Timorese government offices during the CMATS talks in 2004 and did not negotiate in good faith.

The arbitration became public after Australian Secret Intelligence Service (ASIO) raided the home of a former spy, identified as Witness K, and the offices of Canberra-based lawyer Bernard Collaery.

Australia and Timor have struggled to agree on oil exploration in the Timor Sea. Photo: Getty

In 2014, Timor agreed to a request from Australia to put the proceedings on hold to allow further talks.

Last year, Australia returned the seized information without acknowledging it had violated Timor’s sovereign rights.

The Timorese can’t take their case to the International Court of Justice under the UN Convention on the Law of the Sea because Australia withdrew (in 2002) from a clause that allowed compulsory dispute resolution.

Gusmao says that Timor agreed to suspend the initial legal action because they thought it would lead to negotiations over the maritime border.

“For eight months, it was a game. When we started to talk the people sent to us said: ‘oh we are junior, we cannot say anything and we just came to listen’.”

Turnbull refuses to budge

This year, the current Timor Prime Minister wrote to Australian PM Malcolm Turnbull again asking for talks on a maritime boundary.

“His response was about all and about nothing,” Gusmao said.

Gusmao contacted Malcolm Turnbull to discuss the Timor Sea. Photo: AAP

“The same language that we experienced for years … that it was better for you than for us because of 90-10 per cent [split].”

Timor has now sought compulsory conciliation under the United Nations Convention on the Law of the Sea (UNCOS), which included a meeting in New York last month between Gusmao and UN Secretary General Ban Ki-Moon.

Gusmao is quietly indignant that Australia has fixed its maritime boundaries with all other nations, but has refused to do the same with the two per cent of its border shared with Timor.

“Look, when we understood this, we said no way, it is not very fair from a big country, a developed country, to a teeny country and an underdeveloped country,” he said.

“We hope in this that the national interest will be the national honour, to right the wrong.”

Labor has agreed to negotiate a maritime boundary, but the Liberal-National Coalition has yet to budge.

Still, Gusmao and the Timorese live in hope.