His statement followed an earlier ruling by a taxation committee in which a further extension of the deadline to impose back taxes on Thaksin was deemed not to be legal after the statute of limitations had already expired.

Prayut said the government had to be careful in handling this matter because it could also be held accountable for violating Article 157 of the Criminal Code for negligence of official duty if nothing were done.

However, the government will ensure it strictly follows due process in pursuing the matter, as well as other cases involving former politicians who held public office in the two previous governments of Abhisit Vejjajiva and Yingluck Shinawatra.

At least four former politicians were named as those whose tax records are under investigation due to the possession of more assets following their time in public office.

They include Pongsak Rattanapongpaisal, former energy minister; Nuttawut Saikreu, former deputy agriculture minister; Niwattamrong Boonsongpaisal, former deputy premier; and Suchat Chokechaiwattakorn, former deputy transport minister.