(a) No official or employee of the executive, legislative, or judicial branch of state government shall be reimbursed from public funds for expenses for lodging and air fare incurred in the performance of his duties unless a bill, receipt, or similar supporting document showing payment therefor or an explanation of the absence of such documentation shall be submitted when applying for reimbursement.

(b) The requirements of subsection (a) of this Code section shall be in addition to any other requirements relative to reimbursement for any expenses incurred by any such official or employee in the performance of his duties which are now or hereafter provided for by law. The requirements of subsection (a) of this Code section also shall not preclude the promulgation by any agency of the executive, legislative, or judicial branch of state government of any rule or regulation or policy relative to reimbursement for any expenses.