While workers try to mend a volatile broken pipe, iwi and conservationists want assurance the rupture in the Marsden Pt to Auckland aviation line will not endanger wildlife.
Patuharakeke, the hapu that holds mana whenua over Marsden Pt, is ''deeply concerned'' about the potential leak of jet fuel into waterways, including the Ruakaka River, estuary and groundwater.
''This is a national issue that all New Zealanders have a vested interest in. As mana whenua, Patuharakeke has a duty as kaitiaki to take care of the environment,'' Patuharakeke kaumatua Paraire Pirihi said.
"We take this leak extremely seriously, it could have been a major catastrophe.''
Patuharakeke Te Iwi Trust Board spokeswoman Juliane Chetham said the leak could have a major impact on an area already in a fragile environmental and ecological state.
The trust has approached Refining New Zealand to ensure trustees can go on site as soon as possible to observe the recovery operation.
The Green Party has described the oil spill as a "debacle" and demanded the Northland Regional Council (NRC) and Refining NZ release scientific evidence to support claims of no environmental damage.
Those concerns mirror Forest and Bird's fears about a possible impact on the critically endangered fairy tern, rare dotterels and kuaka/godwits. Thousands of the latter are due to return soon from their migration to Siberia.
Whangarei Greens candidate Ash Holwell said while the rupture highlighted such concerns as well as the supply issue, there was no other way to shift oil down the line.
"It's a shock to know that some of our infrastructure is so vulnerable, but there is no alternative [to the pipeline]."
He suggested rail, if there were a line to Marsden Pt, would be a viable aid to helping future-proof New Zealand's oil supply.
NRC and Department of Conservation (DoC) staff have been monitoring the spill location and nearby reserves daily since the fault was discovered on Thursday.
NRC regulatory services group manager Colin Dall said the leak had been contained on-site and the contaminated soil collected.
Measures since Thursday included installing dams, booms and other equipment to contain, isolate and separate any aviation fuel from water.
Between 70,000 and 80,000 litres escaped into a farmer's culvert but the NRC is satisfied it did not get into local waterways.
"In terms of the environmental side, it's under control," Mr Dall said. "We think the effects have been very localised."
While the break had had a serious effect on airline flights and the travelling public, "as an environmental incident, it's not a major," he said.
The NRC will sample groundwater bores and, as with any spill, investigate the circumstances leading up to it.