Judiciary Act 1903

The High Court in the exercise of its original jurisdiction in any cause or matter pending before it, whether originated in the High Court or removed into it from another Court, shall have power to grant, and shall grant, either absolutely or on such terms and conditions as are just, all such remedies whatsoever as any of the parties thereto are entitled to in respect of any legal or equitable claim properly brought forward by them respectively in the cause or matter; so that as far as possible all matters in controversy between the parties regarding the cause of action, or arising out of or connected with the cause of action, may be completely and finally determined, and all multiplicity of legal proceedings concerning any of such matters may be avoided.