Power as to matters of evidence (National Assembly)
Section 89(1) · 1999 Constitution (2004 edition)
What Constitution says
(1) For the purposes of any investigation under section 88 of this Constitutional and subject to the provisions thereof, the Senate or the House of Representatives or a committee appointed in accordance with section 62 of this Constitution shall have power to - (a) procure all such evidence, written or oral, direct or circumstantial, as it may think necessary or desirable, and examine all persons as witnesses whose evidence may be material or relevant to the subject matter; (b) require such evidence to be given on oath; (c) summon any person in Nigeria to give evidence at any place or produce any document or other thing in his possession or under his control, and examine him as a witness and require him to produce any document or other thing in his possession or under his control, subject to all just exceptions; and (d) issue a warrant to compel the attendance of any person who, after having been summoned to attend, fails, refuses or neglects to do so and does not excuse such failure, refusal or neglect to the satisfaction of the House or the committee in question, and order him to pay all costs which may have been occasioned in compelling his attendance or by reason of his failure, refusal or neglect to obey the summons, and also to impose such fine as may be prescribed for any such failure, refused or neglect; and any fine so imposed shall be recoverable in the same manner as a fine imposed by a court of law.
This is the 1999 Constitution as published in 2004. Later amendments aren't included yet, so a section may have changed since.
Original source
Official Gazette · CFRN 1999 official PDF · printed page 55–56. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections