This page provides background information on the treaty between New Zealand and Australia on the EEZ and Continental Shelf Boundaries.
In July 2004, New Zealand and Australia signed the 'Treaty between the Government of Australia and the Government of New Zealand establishing certain Exclusive Economic Zone and Continental Shelf Boundaries'.
The treaty definitively settles the maritime boundaries between the two countries in the Tasman Sea and adjacent areas of the south-western Pacific Ocean.
Read the media statement NZ, Australia sign Treaty settling maritime boundaries from the Minister of Foreign Affairs and Trade on the Beehive website.
What does the Treaty do?
It establishes and describes the boundary lines between Australia's and New Zealand's exclusive economic zones and continental shelf.
What is the exclusive economic zone?
The exclusive economic zone (EEZ) is the area extending out 200 nautical miles (M) from the coast, including both the sea and the seabed. It is measured from the baseline of the territorial sea, generally the low water line.
Within the EEZ, the coastal State has sovereign rights over the living and non-living resources of the sea and the sea-bed.
The continental shelf
The continental shelf is the seabed and the subsoil beyond the territorial sea out to 200 nautical miles from the coast or, where the 'natural prolongation' of the land territory extends beyond that limit, to the outer edge of the continental margin.
In no case, can it extend beyond the greater of 350 nautical miles from the baseline or 100 nautical miles from the 2500m isobath (a line connecting all points lying at a depth of 2500 metres).
On the continental shelf, the coastal State exercises sovereign rights over the non-living resources and sedentary living organisms (such as sponges and molluscs).
Why was it necessary to conclude the Treaty?
Fixing the maritime boundaries gives certainty of jurisdiction where the legitimate maritime claims of neighbouring states overlap.
Australia and New Zealand will submit information on their continental shelves (in 2004 and 2006 respectively) to the Commission on the Limits of the Continental Shelf. The Commission will make recommendations based on that information about the limits of each country's continental shelf.
Establishing agreed boundaries ensures that both New Zealand and Australia will be supportive of each other's submissions to the Commission.
What benefits will the Treaty bring?
The Treaty confirms the median line boundary between the overlapping EEZs that has been observed de facto by the two countries for more than two decades. It gives certainty on the extent of these zones.
The Treaty establishes the boundary between the areas of continental shelf beyond 200M claimed by Australia and New Zealand in the Tasman Sea and adjacent areas of the south-western South Pacific and Southern Oceans.
Each country will also exercise sovereign rights over additional areas of continental shelf beyond 200M outside the areas covered in the negotiations.
The establishment of these boundaries provides both countries with certainty of jurisdiction over the relevant offshore resources within their boundaries, such as fisheries and petroleum and other mineral or biological resources of the seabed.
What kind of jurisdiction do the two countries have over the continental shelf?
Under UNCLOS, a coastal State exercises 'sovereign rights for the purpose of exploring' the continental shelf and 'exploiting its natural resources'.
The natural resources of the continental shelf are:
- mineral and other non-living resources of the sea-bed and subsoil
- living organisms belonging to sedentary species, such as sponges and molluscs.
Are there hydrocarbon deposits on the continental shelf subject to the Treaty?
The hydrocarbon potential of most areas of continental shelf beyond 200M that have been delimited by the Treaty is largely unknown, but in general, is not likely to be high.
What were the main issues that arose in the negotiations?
During negotiations, the relevant issues included the relative length of coastlines, the effect of islands, and the distances from relevant coastlines, as well as geomorphological factors such as natural prolongation and the legal and technical case for connectivity of the continental shelf.
Why are the lines drawn as they are?
The boundary has two parts:
- in the north, dividing Australia and New Zealand EEZs and continental shelf in the region extending from Lord Howe Rise, past Lord Howe and Norfolk Islands to Three Kings Ridge
- in the south, separating the EEZs and continental shelves between Macquarie Island and Campbell and Auckland Islands.
What further boundary treaties need to be negotiated?
Australia and New Zealand have yet to delimit the maritime spaces off their respective Antarctic territories, but otherwise have now settled all maritime boundaries between them.
Australia has still to conclude maritime boundary treaties with East Timor, France and Norway.
New Zealand has still to conclude maritime boundary treaties with Fiji and Tonga.