Mr Tarit was speaking as secretary-general of the government’s Centre for the Administration of Peace and Order (Capo),
The court has been asked to rule on the status of Ms Yingluck and her cabinet for her wrongful removal of Thawil Pliensri as the secretary-general of the National Security Council.
The Administrative Court and the Supreme Administrative Court have ruled that the transfer was unjustified and unlawful because it paved the way for her relative to be promoted to the position of national police chief.
In his statement, Mr Tarit said the Constitutional Court always based its rulings on regulations that it had set itself, and it still failed to have these regulations supported by an act of parliament as the constitution required.
Mr Tarit claimed the delay raises suspicions as to whether the Constitutional Court’s rulings are just.
Mr Tarit, who is director-general of the Department of Special Investigation (DSI), said the Constitutional Court has been criticised for issuing rulings that infringe on the power of other organisations. He cited the court’s rulings against charter amendments on the make-up of the Senate, the Feb 2 election and a bill for the government to borrow 2 trillion baht to fund transport development projects.
Regarding the Constitutional Court's handling of the case on the prime minister's status, Mr Tarit said he hoped the court would apply the same standard as in its previous ruling against late prime minister Samak Sundaravej.
The court disqualified Mr Samak as the prime minister in 2008 as he had hosted TV shows and received payment. The disqualification had taken effect immediately, but was not applied to members of his cabinet.
Mr Tarit said if the Constitutional Court rules differently in Ms Yingluck’s case, it could be accused of lacking a standard and reliability. If the ruling is unconstitutional, it could lead to a clash between conflicting demonstrators, he said.