11   Answers and documents

(1)  A witness summoned to attend or appearing before the commission shall not be entitled, except as otherwise provided in this section and section 127 (Religious confessions) of the Evidence Act 1995, to refuse:

(a)  to be sworn or to make an affirmation,

(b)  to answer any question relevant to the inquiry put to the witness by any of the commissioners,

(c)  to produce any document or other thing in the witness’s custody or control which the witness is required by the summons to produce.

(2)  Nothing in this section shall make it compulsory for any witness:

(a)  to answer any question or produce any document or other thing if the witness has a reasonable excuse for refusing,

(b)  to disclose any secret process of manufacture.

(3)  A witness summoned to attend or appearing before the commission shall have the same protection, and shall in addition to the penalties provided by this Act be subject to the same liabilities in any civil or criminal proceeding as a witness in any case tried in the Supreme Court.

(4)  If a commission obtains for the purposes of the inquiry any document or other thing or any information that is provided voluntarily by a person, subsection (3) applies to the person as if the person were a witness appearing before the commission.