Newcastle and Hunter River Steamship Co Ltd v Attorney-General for the Commonwealth

The parties to this case were the Newcastle and Hunter River Steamship Co. Ltd. and other shipping companies, along with the State of Western Australia, as plaintiffs, and the Attorney-General for the Commonwealth and the Minister for Trade and Customs as defendants. The dispute concerned the validity of various provisions of the Navigation Act 1912-1920 and associated regulations, which the plaintiffs argued exceeded the legislative power of the Commonwealth Parliament, particularly in their application to ships engaged solely in intra-state trade. The matter came before the High Court of Australia by way of demurrer to the plaintiffs' statement of claim.

The central legal issues before the Court were: first, whether the Commonwealth Parliament possessed the constitutional power to legislate regarding the manning and accommodation of ships engaged exclusively in intra-state trade and commerce; and second, if certain provisions of the Act were found to be beyond the Commonwealth's power, whether those invalid provisions were severable from the rest of the Act, or if their inclusion rendered the entire Act or significant portions thereof invalid. The plaintiffs contended that the Act, as applied to their intra-state operations, imposed undue financial burdens and operational impediments, and that such application was constitutionally impermissible.

The Court held that the Commonwealth Parliament's power to legislate with respect to navigation and shipping, derived from sections 51(i) and 98 of the Constitution, is limited to that which is relevant to inter-state and foreign trade and commerce. Consequently, provisions of the Navigation Act and its regulations that purport to prescribe rules for ships engaged solely in the domestic trade of a State were found to be beyond the Parliament's legislative power and thus invalid to that extent. However, the Court also considered section 2(2) of the Act, which declared that the Act should be read subject to the Constitution and not exceed Commonwealth legislative power, and that where an enactment would otherwise be in excess of power, it should be valid to the extent it was not. The Court interpreted this provision as a legislative declaration that valid and invalid provisions, even if interwoven, should not cause the entire enactment to fail, preserving the valid parts. Therefore, the Court found that neither the whole Act nor specific sections were rendered invalid merely by the inclusion of provisions relating to intra-state shipping alongside those concerning inter-state and foreign trade.