The Government is looking at joining a long-standing international standard addressing air pollution and emissions from ships but a researcher says it's embarrassing New Zealand hasn't yet made the move.
Victoria University maritime law expert Dr Bevan Marten said New Zealand remained one of just four countries in the OECD that has not yet signed up to Annex VI of the International Convention for the Prevention of Pollution from Ships (Marpol).
"This international standard has been around for years. The fact that New Zealand hasn't signed up to it makes us a real outlier. It's quite embarrassing.
"Any country we want to compare ourselves to, from Australia to Europe, as well as lots of Pacific Islands, has ratified it."
Annex VI was agreed in 1997 and took effect internationally in 2005.
It deals primarily with ships' fuel quality and engine efficiency but is also being used by the International Maritime Organisation (IMO) as the vehicle for discussions around greenhouse gas emissions from shipping.
Further to the reputational risk of not being seen to address the global challenge of air pollution, Marten argued New Zealand risked not having a credible voice at IMO when the next steps for shipping's response to greenhouse gases were discussed.
"We are saying that climate change is important, but any other country could turn around and ask why we haven't signed up to this agreement."
Some of the proposals at IMO for addressing the reduction in shipping-related emissions would have serious economic effect on New Zealand, as they would involve ships that travel longer distances having to pay higher levies, he said.
"New Zealand's geographic isolation makes us vulnerable and with our international trading interests we need the government to take a strong and effective line when these issues are raised."
Without having ratified Annex VI, New Zealand lacked a credible voice in these discussions, he said.
"To date our government policy has been that we're just a small country with no international shipping fleet of our own, so it doesn't really matter, but this is disingenuous and irresponsible."
Marten said there were also practical health benefits to signing the agreement.
Air quality monitoring in Auckland, Tauranga and Wellington suggested shipping was a key source of sulphur dioxide emissions in these cities.
The burning of bunker fuel oil is also a significant source of nitrogen oxides and fine particulates, which were known to be carcinogenic.
"If you're pushing your stroller along Auckland waterfront during a busy day at the port, you and your child could be breathing in some pretty toxic stuff. These are nasty pollutants.
"Ratifying Annex VI would demonstrate that the government takes these issues seriously."
Marten is calling for the ratification of Annex VI to be made a priority on the Ministry of Transport's work programme.
"The move would have practical benefits, both in addressing the issue of clean air that is dear to New Zealanders' hearts, and in giving New Zealand a stronger voice at the international level as the issue of air pollution becomes increasingly important at IMO."
Ministry of Transport aviation and maritime general manager Nick Brown told the Herald the ministry had begun assess whether New Zealand should join.
"We will be investigating the full implications for New Zealand, including the costs and benefits of signing up, as part of our 2017 work programme," he said.
"We have already started to talk to shipping industry groups and stakeholders, and we have committed to provide advice to the Government by September 2017. Ministers will then make a decision."
Responding to Marten's concerns around environmental effects, Brown said the maritime transport of cargo was relatively more energy efficient, producing fewer greenhouse gas emissions, than other transport modes in terms of tonne-kilometre freight movement.
New Zealand had a "modest level" of maritime traffic compared to international levels, he said.
About 1500 ships ply New Zealand's coasts each year; of 1588 travelling around the country's waters last year, 101 were cruise ships.
Brown said New Zealand's long-time involvement in the IMO "reflects the strong interest we have in ensuring effective international rules for safe and secure shipping, and protecting the marine environment against ship pollution".
Shipping pollution laws in New Zealand
• Regulation 15 of the Resource Management (Marine Pollution) Regulations 1998 states that: "Any person may discharge, in the coastal marine area, a contaminant that is incidental to, or derived from, or generated during, the operations listed in Schedule 4 as the normal operations of a ship or offshore installation."
• This regulation means that air discharges from ship exhausts are permitted under the Resource Management Act 1991 and regional plans cannot make rules that restrict these discharges.
• The Ministry of Transport oversees some rules relating to particulate emission standards for vehicles and the Engine Fuel Specifications Regulations 2011.