
Prime Minister Abhisit Vejjajiva said it was necessary to hold the summit in Hua Hin, 150 kilometres south-west of Bangkok, "to preserve our image."
The anti-government Democratic Alliance Against Dictatorship (DAAD) has vowed to block the summit in a tit-for-tat move against the People's Alliance for Democracy (PAD), which scuttled plans to hold the summit last year when Thailand was under a different government.
The PAD first forced the government of former premier Somchai Wongsawat to shift plans to host the summit from Bangkok to Chiang Mai, 700 kilometres north of the capital, and then succeeded in postponing the regional forum - originally scheduled to be held in mid-December - when they seized and closed Bangkok's two airports on November 26 to December 3.
Thailand is now under a new coalition government, led by Democrat Party leader Abhisit, but it faces a similar plague of protests.
The DAAD, or "red shirts," have called for Abhisit to resign, protesting every public function he hosts, much as the PAD, or "yellow shirts," did to the previous government.
Thailand proposed several new dates for the Asean summit, but has now settled for February 27 to March 1.
Foreign Ministry sources said China, a key Asean partner, will not be able to attend the summit if it is held in late February.
"It happens that the last date of February 27 to March 1, China has another important prior engagement," said Thai Foreign Ministry spokesman Tharit Charungvat.
China will be busy with its National Congress in late February and early March.
Although China is not a member of Asean, it has come to play a leading role at recent summits as international attention shifted away from South-East Asia towards China as an upcoming economic and political powerhouse.
China, along with Japan and South Korea, has attended past Asean summits to participate in Asean-Plus 3 summits on the sidelines of the regional gathering.
Abhisit said there will be two summits, with a second scheduled later this year to be held between Asean and its main dialogue partners.
Asean comprises Brunei, Cambodia, Indonesia, Laos, Malaysia, Burma, Philippines, Singapore, Thailand and Vietnam.
The 14th summit is expected to concentrate on the economic challenges posed to the region by the US financial meltdown and resulting recessions in the US, Europe and Japan - the three main markets for Asia's exports and services.