MANILA - US Secretary of State Hillary Clinton said Friday she did not expect the Myanmar junta to soften its stance on detained democracy leader Aung San Suu Kyi anytime soon, despite a diplomatic offensive.

"I doubt it. This is a long term effort that requires a lot of patience," Clinton told a public forum in Manila when asked whether the junta was likely to loosen curbs on Suu Kyi after a high-profile leaders' meeting this weekend.

The meeting in Singapore is set to see Myanmar Prime Minister Thein Sein and other leaders of the 10-member Association of Southeast Asian Nations hold their first ever collective talks with a US president.

The meeting, on the sidelines of the Asia Pacific Economic Cooperation summit, would also mark the first time in 43 years a US president has met a Myanmar leader.

It comes as US President Barack Obama changes a long-time US policy of political isolation in regards to Myanmar's undemocratic leaders, in favour of one of cautious diplomatic engagement.

Nevertheless, Clinton repeated comments made during earlier stages of her Asian trip in praise of Suu Kyi, and her disdain for the generals of the country formerly known as Burma.

"There is no doubt in my mind that the leadership in Burma is on the wrong side of history. It is just a question of how long they stay there," Clinton said at the nationally televised forum.

But she emphasised that "things don't happen overnight. It takes a while".

Suu Kyi's party won the 1990 general elections, but the ruling junta never recognised her victory and has had her in detention for most of the time since then.

Myanmar's generals are preparing to hold elections again next year, but Suu Kyi has called for a boycott, calling them a sham designed to legitimise the junta.