Refining NZ is confident it has enough warning signs over its 2m deep pipeline to Auckland, but it will still look to see if more can be done to prevent it being damaged again.

Causes of the rupture on Thursday in the Marsden Point to South Auckland fuel line will likely be the subject of various inquiries and future-proof planning after the line had to be shut down for repairs and led to major disruption to fuel supplies.

The 170km long, 2m deep pipeline is marked by white posts marching through paddocks, hazard signs on every roadside fence it passes under and its path across private land signalled on every property's local council Land Information Memorandum (LIM) and other documents.

So is Refining NZ satisfied it has enough measures in place to show where the Ruakaka - Auckland Pipeline (RAP) is, and protect it from the kind of damage or corrosion that may have caused last Thursday's failure?

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"Yes, we are," Refining NZ spokesman Peter Heath said yesterday.

"As part of the wash up that will take place as a result of this issue there will be careful discussion around whether there is more we could be doing."

The exact cause of the pipeline rupture is still being investigated. And while swamp kauri expert Milton Randell said the damage was caused by somebody digging for swamp kauri Refining NZ has said that was not the case. This has been backed up by the site's nearest neighbour.

Whangarei District Plan rules applying to the land under which the 275mm diameter pipe crosses prohibit fences or structures above it, planting trees, disturbing the soil deeper than 40cm or doing anything on the designated corridor that could impact the pipeline without Refining NZ consent.

Written consent by Refining NZ is required for any trenching and excavation or drilling in the corridor.

A close neighbour of the Ruakaka leak site, Brendon Rudman whose Marsden Pt Rd home overlooks it, said there had been excavation for swamp kauri on other farms in the area, but he had seen none at the spill site or anywhere near the pipe corridor for some time.

Mr Rudman said Refining NZ had dropped leaflets in local mailboxes apologising for any disruption but no one had spoken to affected householders he knew.

His family had been bothered initially by the strong fuel smell and the subsequent noise and lights of the late night recovery job.

"It's a disturbance but, hey, they've got a big job to do. We'd have liked someone to knock on the door and say such and such is happening, though."

His son Jordan said he noticed the very strong smell when he got home from work on Thursday, and at first thought his truck had sprung a leak.

"We've lived here for 26 years and we've never seen a leak. Something would have to dig really deep to reach that line."

Brendon Rudman, whose house is near the site said the smell and noise were annoying but the refinery is doing a job. Photo/Michael Cunningham
Brendon Rudman, whose house is near the site said the smell and noise were annoying but the refinery is doing a job. Photo/Michael Cunningham

The repair activities have progressed well, said Refining NZ's Greg McNeill. The refinery had also made progress on a truck-loading option, subject to product quality and safety reviews from the relevant stakeholders.

"We remain on track to deliver jet fuel into Wiri between midday Sunday, September 24 and midday Tuesday the 26th.

''Settling, recertification and transport to the airport for use takes another 30 hours."

Air New Zealand flights in and out of Whangarei have not been disrupted at this stage.

The break has caused other problems though. The leak, 8km south of the Marsden Point refinery, is this week expected to affect about 2000 travellers a day as jet fuel is rationed. More than 30 flights, including 12 international trips, were cancelled yesterday.

• There is only one pipeline for the three types of refined oil sent via the Ruakaka Auckland Pipeline. They are pumped in batches with "plugs" separating the flows of diesel, petrol or jet fuel. At the South Auckland storage tank destination, the "interface" - where different fuels might merge - is diverted to a separator and the pure flows of each fuel sent to the appropriate holding tanks.