Singapore, Nov 20: Southeast Asian nations were set to sign a charter on Tuesday that aims for free trade and human rights, but controversy over member Myanmar has marred the landmark deal.

The Association of South East Asian Nations has spurned Western calls to pressure Myanmar over the junta's crackdown on pro-demcoracy protests, prompting criticism the charter was toothless.

ASEAN has called on Myanmar to work with the United Nations towards democracy and to release political detainees, including opposition leader Aung San Suu Kyi, though members Vietnam and Laos said, they had no plans for democracy.

"Myanmar has not fought to take out words like 'human rights' and 'democracy'. They are not against putting these down as an aspiration, but they ask for more time," ASEAN Secretary-General Ong Keng Yong told in an interview.

ASEAN has barred the U.N. envoy for Myanmar, Ibrahim Gambari, from briefing the summit, after objections from Myanmar's Prime Minister Thein Sein and other members, citing the group's policy of non-intereference in each other domestic's affairs.

"Thein Sein opposed it. He said that nobody has the right to brief on Myanmar but him," an Asian diplomat told Reuters.

ASEAN officials and Filipino diplomats said China, Myanmar's closest ally, had also asked ASEAN to refrain from public comments on Myanmar.

But Philippine President Gloria Macapagal Arroyo, herself criticised for human rights abuses, took a firmer line against the military junta, saying if it did not move toward democracy the Philippine Congress might not ratify the charter.

Japanese Foreign Minister Masahiko Komura also urged Myamar to accept Gambari's proposals for democracy, after a meeting with his counterpart from the junta.

"It would be better if envoy Gambari has a chance to give an explanation at every possible opportunity. It would have been good for Myanmar. But this is something ASEAN has decided," Komura told reporters.

ASEAN leaders will have meetings with the heads of Japan, China and South Korea in the ASEAN+3 group later on Tuesday, and with the ASEAN+6 (also called the East Asian Summit and including India, Australia and New Zealand) on Wednesday.

After years of haggling, the 40-year-old group's charter contains a blueprint to create an EU-style, free-trade bloc, though the past year has been one of political regression.

In September, just a year after the Thai military overthrew a democratically elected government, Myanmar ordered soldiers to shoot at unarmed monks and protestors.

Asked why a one-party state would sign a charter that aims to strengthen democracy, Vietnam's Prime Minister Nguyen Tan Dung underlined the charter's principles of non-interference.

"The one-party system is the choice of the Vietnamese people. I don't think there should be any imposition from any countries," Dung told Reuters in an interview.

While ASEAN's democratisation process has gone spectacularly off the rails, the regional economy faces daunting challenges.

Despite strong economic growth in all ASEAN member countries, regional trade has shrunk as China's rapid growth forces former Southeast Asian tigers such as Malaysia into an old role as plantation economies and suppliers of raw materials and half-finished goods.

An Economist Intelligence Unit shows the total amount of trade among ASEAN countries fell from 22.4% of the bloc's total trade in 2000 to 20.9% in 2006.

"This does not augur well for ASEAN's aspirations to become a single trading bloc," EIU director Charles Goddard said.