"I am deeply saddened by the extended detention of Aung San Suu Kyi to a further period of house arrest," the Tibetan leader said in a statement posted on his Official website Wednesday.
"As a fellow Buddhist, I would like to once again appeal to the Burmese authorities to show magnanimity and understanding by releasing her. Doing so will not only contribute towards reconciliation but also will be a goodwill gesture."
Myanmar pro-democracy leader was found guilty on Tuesday of breaking the terms of her house arrest. In the past the Asean group has been criticized for not taking a tougher stance on Burma's rights record.
The United State, the European Union, Britain and France are among those who have condemned the verdict, but neighbor China said the world should respect Burma's laws.
Myanmar opposition leader Aung San Suu Kyi who has been detained for nearly 14 of the last 20 years, mostly under house arrest, faces up to five years in prison on charges that she harbored an American who swam to her lakeside villa earlier this year - a violation of the terms of her house arrest.