The Thai Airways International (THAI) union has questioned the appointment of the company's former president, Charamporn Jotikasthira, as a member of the airline's committee on strategies and reform.
THAI labour union president Damrong Waiyakanee said it was puzzling why Mr Charamporn was now a member of the panel because when he was president, he had hired foreign firms to advise on strategy and reform.
Also, some employees doubted the effectiveness of the reforms carried out by Mr Charamporn while he led the company.
The THAI board approved Mr Charamporn's appointment to the reform and strategy panel.
The move, announced last Wednesday following the resolution of the board chaired by permanent secretary for energy Areepong Bhoocha-Oom, will retroactively take effect from Feb 10, one day after Mr Charamporn's term as the THAI president ended.
The strategy and reform panel needs new members after several years of operation.
The panel has some major responsibilities including scrutinising the company's strategies and reform plans before forwarding them to the board as well as giving advice to THAI administrators.
The reform undertaken during Mr Charamporn's tenure as THAI president is in its third phase.
The first phase, which began two years ago, involved turning the national carrier around by stemming the "financial bleeding" from heavy losses suffered by the company.
The second phase in the so-called strength building period was related to improving the airline's ticketing system and streamlining the automated fare management that enabled it to sell tickets to optimise profitability.
The phase also involved the rebranding of the airline, sprucing up its inflight interior and improving services. The airline is currently in its third phase of reform focusing on ways to sustain its growth.
A THAI source said the reform panel will also be responsible for considering a plan to acquire 63 aircraft, currently under watch by the labour union.
Mr Damrong also said he was satisfied with the company's decision to increase salaries for its employees by 6% although it was less than the maximum rate of 7.5% approved by the cabinet.
The 6% rise is acceptable because THAI has promised to handle other financial issues for its staff, including tax expenses, monthly contributions to the staff provident fund and overtime payments, Mr Damrong said.