In a press conference, President Arroyo rejected calls from several senators for a diplomatic initiative against Myanmar.
"It would be imprudent for the Philippines because if Myanmar loses the chairmanship, we are the chairman," she said.
The senators have urged Malacañang to block Myanmar from chairing ASEAN because of political and human rights violations in the military-ruled country, including the detention of Nobel Peace Prize laureate, Aung San Suu Kyi.
Under an alphabetical rotation schedule, the Philippines will chair ASEAN in 2007.
ASEAN is divided over Myanmar. The Philippines, Singapore and Malaysia are pushing for democratic change in Myanmar, while Cambodia, Vietnam and Laos have invoked the long-held ASEAN tradition of non-interference in the internal affairs of members.
Mrs. Arroyo said informal discussions on the issue might take place on the sidelines of the Asian-African summit in Jakarta, Indonesia.
In a recent retreat in Mactan, ASEAN foreign ministers decided to defer any decision until a ministerial meeting in Laos in July.
But the United States and the European Union, which have imposed sanctions on Myanmar, have been pressuring the regional grouping to take action.
Foreign Affairs Secretary Alberto Romulo said he expects "vigorous debates" over Myanmar amid continued pressure from the US and the EU.