UNCLOS determines a country's rights and duties over the water column and seabed These delineations of different marine jurisdictions do not necessarily bear a relationship to the boundaries of ocean ecosystems. This is because their genesis stems from an agreement in 1982 to follow a zone-based approach to maritime jurisdiction. 

New Zealand ratified UNCLOS in 1996. Under this convention, New Zealand’s sovereignty extends out to the edge of the territorial sea, which is 12 nautical miles from New Zealand’s coast, including the coast of all islands.

While the EEZ, which extends seawards from the outer edge of the territorial sea to 200 nautical miles, is not strictly speaking part of New Zealand’s sovereign territory, UNCLOS provides New Zealand with a range of sovereign rights over the EEZ for the purpose of exploring and exploiting, conserving and managing natural resources (including marine life, oil, gas and minerals) and economic exploitation and exploration of the zone (such as for energy production from water, currents and winds). Other countries retain the freedom of navigation and over-flight within New Zealand’s EEZ and can lay submarine cables and pipelines within it. UNCLOS also provides rights over the continental shelf, being the seabed and subsoil beyond its territorial sea to the outer edge of the continental margin or a distance of 200 nautical miles from the baselines where the outer edge of the continental margin does not extend out to that distance. New Zealand as a coastal State, has sovereign rights for the purpose of exploring the continental shelf and exploiting its natural resources. These encompass the exploitation of minerals, gas, and other non-living resources within the seabed and subsoil as well as sedentary species on the seabed, but exclude harvesting mobile fish. 

New Zealand has more limited rights with respect to the extended continental shelf (“ECS”) (i.e. those parts of the continental shelf that extend beyond the EEZ).The boundaries of New Zealand’s ECS were confirmed in 2008 by the United Nations Commission for the Limits of the Continental Shelf.

In exercising its jurisdiction within these various marine areas, New Zealand has a general obligation under UNCLOS to ‘protect and preserve the marine environment’. This includes taking all measures necessary to ‘prevent, reduce and control pollution of the marine environment …’ and ‘to protect and preserve rare or fragile ecosystems as well as the habitat of depleted, threatened or endangered species and other forms of marine life’. New Zealand has other obligations, such as to carry out an environmental impact assessment when activities under its jurisdiction or control may cause substantial pollution of, or significant and harmful changes to, the marine environment. New Zealand also has the obligation to prevent, reduce and control pollution arising from or in connection with seabed activities subject to its jurisdiction. 

Lastly, New Zealand also has an obligation under UNCLOS to promote the ‘optimum utilisation’ of living resources within the EEZ such as through harvesting. However, this obligation is subject to the requirement to ‘ensure through proper conservation and management measures that the maintenance of the living resources in the exclusive economic zone is not endangered by over-exploitation’.

New Zealand ratified the CBD in 1993. Amongst other things, the CBD requires New Zealand to establish a system of protected areas; to regulate where necessary for the protection of threatened species and populations; to require environmental impact assessment of proposed projects that are likely to have significant adverse effects on biological diversity; and to monitor components of biodiversity. The government is also required to promote the protection of ecosystems and natural habitats and the maintenance of viable populations of species in natural surroundings.

MARPOL was adopted in 1973 and modified in 1978. It seeks to prevent pollution from ships, such as accidental oil spills from tankers, and also pollution caused by the discharge of chemicals, harmful substances, sewage and garbage. The convention includes standards which apply to the design and construction of ships, their equipment and operating procedures. It also contains a complete ban on disposal into the sea of all forms of plastic. 

The London Convention was adopted in 1972, with a Protocol adopted in 1996. It prohibits the dumping of waste at sea except for a restricted group of materials. For materials that are exempted from the prohibition, dumping is only permitted if there are no practical opportunities for reuse or recycling and the effects of dumping on the marine environment will be minor. The London protocol adopts a "reverse list" approach: rather than prohibiting the dumping of listed materials, Parties must prohibit the dumping of any waste or other matter that is not listed in Annex 1 of the Protocol. 

Section 11 is not an exclusive list. In addition there is the Convention for the Protection of Natural Resources and Environment of the South Pacific Region 1986, or Noumea Convention, which requires environmental impact assessments and also specifically for public participation to prevent any substantial pollution of, or significant and harmful changes within, the Convention Area. 

Unlike the RMA,

It is clear from section 12 of the EEZ Act that the Crown’s responsibility to give effect to the principles of the Treaty of Waitangi has both procedural (i.e. the way decisions are made) and substantive (i.e. the interests of Māori in the outcome of the decisions made) dimensions.

The first Trans-Tasman Resources Decision-Making Committee noted that the EEZ Act does not expressly require marine consent applicants to consult with iwi however “in understanding and addressing existing interests, some level of consultation appears to be not just good practice but an important element in compiling a robust proposal. Further, a failure to consult adequately with tangata whenua/tangata moana may be seen as culturally offensive and disrespectful.