Section 11(1) in The Disputed Elections (Prime Minister And Speaker) Act, 1977
(1)Subject to the provisions of this Act and of any rules made thereunder, every petition shall be tried by the Authority, as nearly as may be, in accordance with the procedure applicable under the Code of Civil Procedure, 1908 (5 of 1908) to the trial of suits:Provided that the Authority shall have the discretion to refuse, for reasons to be recorded in writing, to examine any witness or witnesses, if it is of the opinion that the evidence of such witness or witnesses is not material for the decision of the petition or that the party tendering such witness or witnesses is doing so on frivolous grounds or with a view to delay the proceedings.
