Tribunals are the Quasi-Judicial Bodies setup by the act of the Parliament thus they are non-constitutional bodies. Originally the constitution does not provided for the tribunals. It was only in 42nd Constitutional Amendment Act that part XIV A was introduced under which Article 323 A and 323 B were introduced.
It says: " Administrative tribunals.—(1) Parliament may, by law, provide for the adjudication or trial by administrative tribunals of disputes and complaints with respect to recruitment and conditions of service of persons appointed to public services and posts in connection with the affairs of the Union or of any State or of any local or other authority within the territory of India or under the control of the Government of India or of any corporation owned or controlled by the Government."
So, Article 323-A provided for the establishment of Administrative tribunals by a parliamentary law and article 323-A, clause 2(a) provided for the establishment of State Administrative tribunals and Joint Administrative Tribunals.
CENTRAL ADMINISTRATIVE TRIBUNALS