Kokako and Matuku carry fuel around New Zealand but could be used to import fuel from further afield in the event of a crisis, the Maritime Union says.
The Maritime Union said ministers heard its concerns that scrapping the country’s two coastal tankers could lead to fuel shortages and higher prices for motorists on the runway.
National Secretary Craig Harrison said those risks were growing as the Ukraine crisis prompted European countries that depend on Russia for energy suppliers to book more tanker capacity to import fuels from further afield.
Harrison said the union met with Deputy Prime Minister Grant Robinson on Friday and had scheduled another meeting with Energy Minister Megan Woods.
Coastal Oil Logistics, jointly owned by Z Energy, BP and Mobil, currently uses two vessels, Kokako and Matukuto transport refined fuels from the Marsden Point Oil Refinery to nine other ports nationwide.
* Fuel companies should be required to store more petrol in New Zealand after the refinery closes
* Taxpayers should pay for any national fuel reserves once the refinery closes, Z says
* No last-minute reprieve for Marsden Point Oil Refinery
* Closure of Marsden Point oil refinery expected to cost 240 jobs
But the three oil majors plan to switch to a different business model once the refinery closes in April.
This will see them abandon the two coastal tankers and import pre-refined fuels to Marsden and these other ports directly from overseas.
Z predicted that the new model will see around 175 tankers visit the country every year and says it will improve the resilience of the industry’s supply chain.
He said in a December report that fully loaded “medium range tanks” – capable of carrying 50,000 tonnes of fuel or more – could drop fuel at Marsden, Mt Maunganui and Lyttelton.
Then, after partially unloading in these larger ports, they could transport smaller cargoes to the other ports “ensuring a flexible and more efficient coastal supply of fuel”, he said.
RNZ’s podcast The Detail in August examined the history of Marsden Point and why some people were warning its closure could put the country’s energy security at risk.
Harrison said the government could not rely on oil company assurances that would work in practice.
He said it would be safer to continue to use the two coastal tankers to distribute fuels from Marsden, using it as a hub, especially in light of the Ukraine crisis.
“Everyone will book their tankers to take care of the northern hemisphere,” he said.
“We believe that with something so important, we shouldn’t just trust Z’s word.”
The market for storage capacity was tightening and a report from Lloyds showed that more new tankers were large vessels over 60,000 tonnes deadweight which would not be economical for coastal distribution and were too large to visit some New Zealand ports, Harrison said.
Using many small tankers to import fuel would increase carbon emissions from shipping, he said.
Coastal Oil’s two onshore tankers had separately proven their worth as additional storage capacity when moored off Marsden Point to store aviation fuel when the Auckland fuel pipeline ruptured in 2017 , Harrison said.
The two tankers could also be used to recover refined fuels from refineries in Australia and Asia in the event of a maritime crisis, he said.
He said the two tankers employed a total of 80 crew members.