The six provinces are Phuket, Pang Nga, Krabi, Surat Thani, Ranong and Chumphon, said an official at the Thai foreign ministry.
Prime Minister Surayud Chulanont would sit together with Malaysia's Prime Minister Abdullah Badawi and Indonesia's President Susilo Bambang Yudhoyono in the third IMT-GT summit here on the side line of Asean summit.
The leaders' endorsement of six additional province would make all 14 provinces in Thailand south were included into the development scheme while Malaysia and Indonesia maintained their eight and ten cities respectively in the IMT-GT.
Established since 1993, the IMT-GT aimed to jointly develop six sectors comprising trade and investment; tourism; Halal goods and service; human resource development; agriculture, fishery and environment; and infrastructure.
The current development projects under the IMT-GT five year road map 2007-2011 outlined by the Asian Development Bank were being implemented after the leaders' approval since a previous summit in the Philippines's Cebu in January this year.
Thailand hopes the development scheme would help uplift living standard in the south, notably the three predominantly Muslim provinces where have been rocked by a spate of violence for long time.
Under the roadmap, the three leaders would also endorse a plan to set up Center for IMT-GT (CIMT) sub-regional coordination in Malaysia to coordinate plan and activities from the member countries as well as from private-sector run Joint Business Council.
Thailand would push ahead IMT-GT economic corridor making more connectivity between southern province of Ranong and Phuket with Indonesia's Aceh, the official at the foreign ministry said.
Thailand and Malaysia share the same boundary and already have many connecting points. A new bridge across Kolok river in Nathiwat's Waeng district and Malaysia's northern Kelantan state would be opened soon.
To boost more tourism activities in the IMT-GT area, the Joint Business Council would launch Visit IMT-GT year 2008 next year. Official launching of the program would be held in Hat Yai between January 11-20. Thailand would organize at least 42 events for the whole year.
As a coordinator for Halal goods and service development sector, Thailand held the first International Halal Expo in conjunction with Maolid Nabi festival in Krabi in February this year. In parallel with the event, there was a seminar to increase cooperation on Halal laboratory network to expand goods and service from the three countries into the $ 200 billion global haral market.
On trade and investment sector, the three countries would set up IMT-GT plaza in Thailand's Pattalung, Malaysia's Port of Dickson and Indonesia's Riau.
Supalak G Khundee
The Nation, Singapore