NUSA DUA, Indonesia (AFP) -- Japanese Prime Minister Junichiro Koizumi will raise the Myanmar issue at next week's ASEAN summit, the grouping's secretary general Ong Keng Yong said Saturday.

Ong was speaking to reporters after senior officials from the Association of Southeast Asian Nations met their dialogue partners from China, Japan and South Korea.

Ong said the Japanese delegate "told us that Koizumi would touch on Myanmar and that he hoped to see the encouraging signs to be further developed".

Japan's Kyodo News Agency said Friday that Koizumi would try to meet Myanmar Prime Minister Khin Nyunt on the sidelines of the summit and would urge him to free opposition leader Aung San Suu Kyi from house arrest.

Aung San Suu Kyi and several members of her National League for Democracy have been detained since a violent clash between her supporters and pro-junta demonstrators on May 30. Japan, Myanmar's biggest donor, suspended new official development assistance to the country in July in protest.

Aung San Suu Kyi was admitted to hospital on September 17 for major gynecological surgery and was last week placed under house arrest for the third time.

Officials from Myanmar and from some fellow ASEAN members have portrayed her transfer from detention at an undisclosed location to house arrest as a positive development.

Ong said many believed that the timing was tailored to ease pressure on Myanmar at the United Nations General Assembly and at the ASEAN summit.

"In that sense it's an important move but others are still not satisfied," he said.

Host Indonesia has been pressing for her complete release before the summit but has described her transfer to house arrest as positive. President Megawati Sukarnoputri declined comment on the issue when approached by AFP Saturday.

It was unclear whether ASEAN foreign ministers and leaders would step up the pressure on the military-ruled state in their talks next week. Officials said Southeast Asian leaders, who shun public confrontations, would probably raise the question of political reforms in "corridor" talks.

They said Indonesia, Myanmar and one or two other members were considering a paragraph in the chairman's closing statement on Myanmar. "It's a delicate issue and we are treading carefully," said one official. "But the key point is to encourage the Myanmar government in their roadmap (toward democracy) and in recognition of positive steps that have been taken."

The crackdown on the opposition sparked fury in the West. In June even ASEAN called for Aung San Suu Kyi's release -- breaking a long tradition of noninterference in each other's affairs.