The United States and the European Union earlier this year renewed sanctions first introduced about 10 years ago against Myanmar over rights violations, including the continued detention of pro-democracy leader Aung San Suu Kyi.

But Association of Southeast Asian Nations (Asean) secretary general Ong Keng Yong said sanctions were not working since member Myanmar was largely immune to them.

"These kinds of sanctions and isolation does not work ... They are happy being isolated because they are left alone to do whatever they want to do," Ong told reporters at the sidelines of the Asia Oil and Gas Conference here.

"What we are saying is perhaps we should look at some other ways of doing it instead of just (keeping) on applying sanctions," he said.

Myanmar's junta extended Aung San Suu Kyi's house arrest by another year late last month, prompting condemnation from the United States, the United Nations and European and Asian nations.

The 61-year-old Nobel peace laureate has spent more than a decade confined to her home. Her party won a landslide victory in 1990 elections but the junta never allowed it to take office.

"Even if you pull out everybody, economic investors, from Myanmar, they are not going to collapse simply because their two big neighbours will be ready to sustain them," Ong said in apparent reference to China and India.

China and India have been criticised for keeping silent over Myanmar's rights abuses.

Ong also said Myanmar would never allow itself to be seen as bowing to international pressure to release the democracy icon.

"That will never happen. You have to ... find a face-saving way out," he said.

Myanmar, which joined Asean in 1997, has embarrassed the regional bloc by steadfastly refusing to introduce democratic reforms.

Ong said the 10-member grouping would continue to engage Myanmar, arguing economic development and growth may help the country to come around.

"This is the sad thing about Asean, the only leverage we have is that Myanmar is a member of Asean. We hope to pressure it to do more," he said.

Ong said Asean foreign ministers would talk to their Myanmar counterpart about Aung San Suu Kyi in a meeting scheduled for July in Manila, although it would not be the main item on the agenda.