South-west Tasmania is a remote and wild part of Australia, one of the few wilderness areas untouched by human development. In the late 1970s the Hydro-Electric Commission, a Tasmanian State government agency, drafted a proposal for the construction of two dams on the Gordon River. The construction of these dams would generate one-third of the State’s electricity needs – however it would also wipe out 35 percent of south-west Tasmania’s wilderness areas, flooding the valley of the nearby Franklin River. The Labor State government made the area a National Park in 1981, as an acknowledgement of the area’s natural significance. But an election the following year brought in a Liberal State government that supported the project. New Tasmanian Premier Robin Gray began moves to formally approve and commence the damming of the Gordon. With the majority of Tasmanians supporting the project in an 1981 plebiscite, it looked as if the dams would proceed.
This initiated an intense public campaign by several conservationist groups, the most prominent of which was The Wilderness Society, led by Dr Bob Brown. Thousands of people poured into the wilderness areas, blocking the paths of trucks and construction machinery and attempting to impede construction. More than 1,200 were arrested, including Brown, who spent several days in prison. Anti-dam pressure groups also turned their attention to the Federal government and to international organisations. They had success with the latter – in late 1982 UNESCO, a United Nations agency, declared south-west Tasmania’s wilderness area a World Heritage Site, the second such site after Kakadu National Park. With a Federal election looming in March 1983, the Labor Party, led by Bob Hawke, promised that it would prevent the construction of the dams. Once elected the Hawke government passed the World Heritage Properties Conservation Act (Cth, 1983) which outlined several restrictions on heritage sites, including those deemed as such by international laws or treaties. The practical effect of the new law was that the Commonwealth could halt the building of any dams in the Tasmanian wilderness.
The Tasmanian State government was not prepared to let the matter rest, and pursued the matter in the High Court. Its lawyers argued that the World Heritage Properties Conservation Act was constitutionally invalid because the Commonwealth government had exceeded its Section 51 powers, specifically its authority to legislate for external affairs (xxix) and to regulate corporations (xx). Lawyers for the Federal government argued that under Section 51(xxix) the Commonwealth was entitled to pass legislation in order to give force to an international law or treaty. Because of its environmental focus and concern with State-Federal powers, the case attracted a substantial amount of media and public attention, opinion and commentary.
In July 1983 the High Court returned its judgement. In a 4-3 decision the Court found that while some sections of the Commonwealth legislation were unconstitutional, the section ordering the suspension of dam construction in Tasmania was valid. This marked a radical and somewhat controversial change in the external affairs power in Section 51(xxix), allowing the Commonwealth to make laws codifying or enforcing international treaties, and therefore expanding its law-making power at the expense of the States. Having lost the case, the Tasmanian State government and its hydro-electric commission withdrew its plans to construct dams on the Gordon and Franklin rivers. Today the south-west of Tasmania remains a wilderness area, protected by both Commonwealth law and international treaties.