YANGON (Reuters) -- Myanmar's military rulers resume long drawn out talks on a new constitution on Tuesday, their government under increasing international pressure and cynicism rife about their aims.

One Western diplomat expected the National Convention to wrap up after this session, with the final document to be drafted over the next year or so and some form of referendum among grass roots groups favorable to the generals would follow.

But with opposition leader Aung San Suu Kyi under house arrest and her National League for Democracy boycotting the talks, critics dismiss the convention as a smokescreen for the military to entrench its more than four decades of rule.

The junta, which picked most of the 1,000 or more delegates at the talks, says it is determined to implement its "road map to democracy" announced without a timetable in 2003. A constitution is the first step on that path.

The military, which has run the Southeast Asian nation in various guises since 1962, will focus the session on rules for political parties, elections and "provisions for the transition period", Chief Justice Aung Toe told reporters.

But critics and diplomats point to a key objective of the convention that ensures a "leadership role" for the army, known as the Tatmadaw, in politics.

"The reality is the authorities envisage the Tatmadaw will maintain the prime role in the country," the diplomat said.

Whether the NLD, which won a landslide election in 1990 only to be denied power by the army, will be allowed to run in polls promised under the roadmap is unclear. ------------------------------ Under pressure

The conference resumes as the impoverished country of 55 million comes under the scrutiny of the UN Security Council for the first time.

Washington said late last month it would press for a resolution to put pressure on Yangon to stop jailing political opponents despite China and Russia objecting. The junta then detained five activists on suspicion of "terrorist acts".

Myanmar Information Minister Kyaw Hsan said the move was aimed at installing a pro-Western puppet government in Yangon.

"Nations which value and cherish the truth will surely reject a resolution against Myanmar," he told Reuters.

There are signs that Southeast Asian neighbors may be tiring of criticizing the country's slow progress toward democracy.

A Philippine diplomat said last week the 10-strong Association of Southeast Asian Nations (ASEAN), one of the few international groupings willing to have Myanmar as a member, there would be no "arm twisting" at a Manila summit in December.

A military coup in neighboring Thailand, often held up as a model for democracy in the region until Prime Minister Thaksin Shinawatra was ousted last month, was greeting with "delight" by some junta officials, the diplomat said.

When the coup is reported in Myanmar's state media, stories focus on the Thai generals' moving to oust a corrupt government and ignore their promise of fresh elections in a year. "To them it's a clear example of how Western-style democracy does not work in Myanmar.”