N.Y. Legis. Law § 63
Whenever by resolution of either house, a committee or joint committee duly appointed pursuant thereto shall be directed to conduct an investigation or take testimony, the comptroller shall draw his warrant for the payment of the actual and necessary expenses of the committee or subcommittee having in charge such investigation, inquiry or taking of testimony, and of the officers and employees authorized to accompany them, upon the rendition of an itemized bill of such expenses certified by the chairman of the committee, and approved by the temporary president of the senate in the case of a senate committee, or the speaker of the assembly in the case of an assembly committee, or by both such officers in the case of a joint committee, or by his or their designee or designees, respectively, and upon proof by affidavit or otherwise that the same is due.
Such designation shall be in writing and filed in the office of such officer or officers and in the office of the comptroller and shall remain in effect during the term of office of such officer or officers unless sooner revoked. The approval of any such designee shall be for expenses other than personal service and in amounts not to exceed the sum fixed in such designation for any such item.
N.Y. Legis. Law § 63