East Timor's President Jose Ramos-Horta saw his fledgling nation's parliament as corrupt and ineffective and believed himself both "above local politics" and indispensable, leaked US memos show.

American diplomats also felt Ramos-Horta had let his 1996 Nobel peace prize "go to his head" and that his global ambitions put him at odds with some of Timor's key allies, embassy cables released by WikiLeaks revealed.

Seen as one of the Timor independence movement's heroes, Ramos-Horta was described as a "legendary international negotiator" by US diplomats in Dili ahead of the military mutiny which sparked a violent crisis in 2006.

But less than three years later, following a failed attempt on his life by rebel leader Alfredo Reinado, Ramos-Horta was painted as a more "blemished" character.

"His eagerness to be seen and taken seriously as an international player has led him to make strong and occasionally rash pronouncements on far-flung issues, sometimes counter to Timorese interests," a February 2009 memo said.

Ramos-Horta, now 61, fancied himself as a candidate for United Nations secretary-general, but his outspoken views on Myanmar had led Yangon to veto any move for East Timor to join ASEAN, the memo said.

He had also "seriously irritated" Australia and Indonesia on occasion and "regularly chastises the US" on Cuba.

In September that year Ramos-Horta threatened to resign as president, a post he has held since 2007 elections, after parliament voted against his travel to the United States for the UN General Assembly.

He launched a tirade against the government in private diplomatic discussions, "barely suppressing his anger" as he warned "the parliament was 'playing with fire' by playing political games with him".

"This parliament was corrupt and ineffective, Ramos-Horta charged, and needed to be cleaned up and 'taught a lesson' in the coming months," a September 2009 memo said.

"Ramos-Horta sees himself as above local politics and as an indispensable guarantor of stability in the country," it added.

The president described Prime Minister Xanana Gusmao, once an ally, as "arrogant, but he likes to pretend to be humble", who internal sources said had "an alcohol problem which is impairing his relations with others".

Diplomats cited an April 2008 incident in which "the Prime Minister angered President Ramos-Horta by turning up visibly drunk at a reception in honor of Prince Albert of Monaco".

Oil-rich East Timor won formal independence in 2002, three years after a UN-backed referendum that saw an overwhelming vote to break away from Indonesia, whose 24-year occupation cost an estimated 200,000 lives.