The new directors will be chosen jointly by the Transport and Finance ministries.
The first priority is the controversial plan to move the flag carrier's flights out of Don Mueang Airport to the new airport, Suvarnabhumi.
Second is selecting the airline's new president from some 11 applicants.
Third, the airline, which reported a massive loss of Bt21.3 billion in 2008, will have to implement its business rehabilitation plan quickly to avoid plunging deeper into a liquidity crisis.
Among the 14 THAI directors appointed during the Surayud Chulanont administration from 2006-07, only Attorney-General Chaikasem Nitisiri will be retained, as vice chairman.
This will allow him to chair THAI's shareholders' meeting to vote on a new board.
The 13 other directors stepping down include board chairman Surachai Tansitpong, the permanent secretary for transport; vice chairman Suparut Kawatkul, permanent secretary for finance; Chulasingh Vasantasingh from the Attorney General's Office; and Decha Yoo-Prot from the Navy.
The rest are Pichai Chunhavajira, chief financial officer of PTT; Rangsan Saengsook; Vikrom Koompirochana; Vichit Suraphongchai of Siam Commercial Bank; Visit Limprana of the Food Processing Industry Club; Wisudhi Srisuphan of the Finance Ministry; Vudhichai Sriratanavudhi; Sukumpol Suwanatat of the Defence Ministry; and Amornsuk Noparumpa from Bank of Ayudhya.
Chamsri Sukchotrat, president of the THAI labour union, urged the government to suspend the airline's plan to leave Don Mueang.
She told Prime Minister Abhisit Vejjajiva in a letter that the issue had split the airline's staff as well as customers and the benefits of consolidating operations remained unclear, especially the cost savings.
"We want the PM to help by reconsidering the (March 29) relocation," she said.
Pongpun Sunthornchai, chairman of the House transport committee, also urged the premier to order the Transport Ministry to review its plan to end THAI's operation at Don Mueang.
In a letter to Abhisit, the committee said Suvarnabhumi was not yet ready to be the country's sole aviation hub due to its "limited" capacity.
An academic also petitioned the Central Administrative Court to stop the transport minister and five senior officials responsible for the plan from ending THAI's domestic flights out of Don Mueang.
Somkid Homnate said there was a conflict of interest in proposing the transfer plan. Construction of mass transit routes such as the Airport Rail Express and Mo Chit-Saphan Mai line would make the operation of two airports more convenient, he said.
Big construction companies closely allied with the government would gain from the relocation, as Suvarnabhumi's second-phase expansion would have to go ahead, costing a massive Bt74 billion, he added.