Prayuth sier dette var etter råd fra kongen, mens opposisjonen mener dette gjør at de kan unnlate å følge grunnloven (som de selv har tilpasset sitt regjeringsvelde).
Dette sees på som en stor sak fra opposisjonen, og de mener at Prayuth sine benektelser ikke kan får faktumet om at eden ikke ble fulgt til å forsvinne.
Future Forward lederen MP Piyabutr Saengkanokkul sier at de vil følge saken videre i parlamentet da regjeringen ikke er sverget korrekt inn i henhold til grunnloven.
Prayuth benekter som vanlig å ha gjort noe galt.
Prayut makes light of alleged oath gaffe
Future Forward Party vows to pursue issue in parliament
Prime Minister Prayut Chan-o-cha on Monday shrugged off the opposition's move to hold him to account over an alleged incomplete oath of allegiance, saying the swearing-in ceremony was complete and finished with.
He was responding to growing criticism over an alleged failure to recite the full text of the oath during the cabinet's swearing-in ceremony.
Critics claim the prime minister did not vow to protect and abide by the constitution, which is the final paragraph in Section 161 of the charter. This could render his cabinet illegitimate and unable to perform its duty, they say.
Section 161 prescribes: "Before assuming duties, cabinet ministers must swear an oath to His Majesty the King as follows:
'I (name of minister) swear I will be loyal to His Majesty and perform my duties honestly for the benefits of the country and the people. I will also uphold and comply with the constitution of the kingdom in every aspect'."
However, a video clip on the oath-taking showed Gen Prayut, reading from a note in his hand, and the ministers who repeated the oath after him, left out the last sentence and added "forever" as the last word.
In effect, the oath they took was: "I (name of minister) swear I will be loyal to His Majesty and perform my duties honestly for the benefits of the country and the people forever."