Preawphan earlier sparked criticism when he was appointed police chief, due to his relationship as the brother of Khunying Pojaman - the ex-wife of fugitive prime minister Thaksin Shinawatra.
Preawphan would replace Sathit Limpongpan, whose term was expired along with that of three more directors which included veteran banker Banyong Pongpanich, Surachai Tansitpong, and Chaisak Angkasuwan.
The THAI board of directors today also appointed three more directors - Transport Permanent Secretary Supoth Sublom, ACM ML Suprija Kamalasana, and and Pradit Sintavanarong.