Philippine President Gloria Macapagal Arroyo said in an interview with the Financial Times that ASEAN would negotiate collectively despite the political and economic disparities between its member states.
The Philippines is the current chair of the 10-nation grouping, which includes advanced economies like Singapore as well as poor nations such as Laos and Cambodia.
E.U. officials also say they will include Burma in the negotiations, despite a reluctance to deal with its military government.
Last week, ASEAN and the EU agreed to hold free trade talks after two years of discussion.
ASEAN members are Brunei, Burma, Cambodia, Indonesia, Laos, Malaysia, the Philippines, Singapore, Thailand and Vietnam.