
His reported resignation came a few days after his secretary, Poksak Nilubon, former ambassador to Sweden, resigned, saying he could not serve Samak Government.
The sources said Tej, former permanent secretary for foreign affairs, reasoned his resignation that his wife, Pensri, is sick.
Tej has been appointed to the position on July 27 particularly to handle the Thai-Cambodia dispute on Preah Vihear Temple.
It is still unclear why he wished to resign.
Tej is scheduled to visit Vietnam on September 10 and Indonesia from September 16 - 18.
Tej, 65, was the second foreign minister, under Samak Government.