He said the East Asia summit is the foremost forum for promoting peace, stability and prosperity in the Asia Pacific region.
"This year, we are preparing to launch the negotiations for a Regional Comprehensive Partnership among ASEAN and its FTA partners, including India. This is a giant step towards creation of an economic community in the region. This forum also serves as a useful platform for enhancing cooperation in the region and discussing regional security issues."
The prime minister said he would also be meeting world leaders on the margins of the East Asia summit.
He is expected to have bilateral meeting with Chinese Premier Wen Jiabao on the sidelines of the East Asia summit.
The prime minister said over the past decade India's partnership with the ASEAN has become "strong, comprehensive and multi-faceted".
"The summit in Phnom Penh will give us an opportunity to preview and prepare an ambitious agenda for the summit next month and to take India-ASEAN relationship to a new level."
India is hosting the Commemorative Summit which has the theme 'ASEAN-India Partnership for Peace and Shared Prosperity' in New Delhi Dec 20-21, 2012 to mark the 20th anniversary of this relationship and the 10th anniversary of ASEAN-India Summit-level partnership.
The leaders will also receive the Report of the ASEAN-India Eminent Persons Group.