"Indonesia and other Asean members outside Myanmar are frustrated with the developments in Myanmar, the lack of concrete results from the democratisation process," Hassan told reporters on Monday.
The military government, which has ruled Myanmar since 1962, has refused to accept the election victory in 1990 of a democratic party led by Aung San Suu Kyi, a Nobel peace laureate now held under house arrest.
Instead, the government has published a seven-step "roadmap" to democracy, but Western nations led by the US and the European Union criticised it is as a delaying tactic and have proposed tightening sanctions to force democratic change.
Hassan said he hoped that Myanmar's powerful neighbours, India and China, both of which are eyeing the country's sizeable energy reserves, would also pressure the military government to reform.
"We hope those two countries are not only interested in energy sources, but also help Asean in pushing changes in Myanmar," Hassan said.
Hassan said Myanmar’s lack of progress in implementing significant reform would be discussed among ministers and leaders at the Asean meeting, on the Philippine island of Cebu beginning on Wednesday.
Besides Indonesia, Myanmar and the Philippines, Asean includes Brunei, Cambodia, Laos, Malaysia, Singapore, Thailand and Vietnam.
Last week Myanmar released about 30 political prisoners as part of a larger amnesty of almost 3,000 prisoners.
A pro-democracy group, however, said more than 1,000 political detainees were still being held and that the releases, which coincided with the country’s independence anniversary, were merely "a show".