Australian Constitution - Section 55 - Tax BillLaws imposing taxation shall deal only with the imposition of taxation, and any provision therein dealing with any other matter shall be of no effect.
Laws imposing taxation except laws imposing duties of customs or of excise, shall deal with one subject of taxation only; but laws imposing duties of customs shall deal with duties of customs only, and laws imposing duties of excise shall deal with duties of excise only.