The damaged section of Refining NZ's pipeline is being examined by metallurgical experts to establish what caused the rupture.

The refining company's chief executive, Sjoerd Post, said a specialist firm now had the section which led to an aviation fuel crisis when all piped supplies to Auckland were cut for more than a week.

He said there was no sign of activity around the pipeline in the days before it ruptured on a farm close to Marsden Point.

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The metallurgical firm, Quest Integrity, now had the damaged section.

"Parties are interested in whether we did what we had to do. That will come out in due course."

Post said he did not know whether monitoring would be stepped up.

"I think it's bit too early to judge what we should do differently - it's not for a lack of monitoring that this has happened but clearly we need to draw lessons and potentially do something differently to make sure this doesn't reoccur."

Aviation fuel was pumped down the repaired pipeline yesterday and will be available at Auckland Airport tonight. Petrol and diesel will be transported by the pipe later this week.

Andrew McNaught, representing the fuel industry which supplies airlines, said he was satisfied with his sector's handling the pipeline rupture, saying it could not immediately turn on its response to cart jet fuel by road to Auckland.

Thousands of airline passengers have had travel disrupted during the past eight days and while nearly all flights are running on schedule as jet fuel rationing eases, four international flights were cancelled today and carriers are still having to make expensive and inconvenient fuel stops in Australia and the Pacific.

Airlines were for several days rationed to 30 per cent of normal use of between 3.3 million litres and 4 million litres of aviation fuel a day.

Although the extent of the rupture was becoming known from Friday, September 15, road tankers were not transporting fuel from the Marsden Point refinery to the airport for a week.

A loading facility had to be specially built at the refinery to dispatch aviation fuel.

"Like anything you don't want a whole lot of redundant equipment sitting around which will just lead to cost and cost has to be paid by someone," McNaught said.

"We had trucks up and running within a matter of days. From an industry perspective I'm very comfortable with the way we've reacted."

He said the fuel industry had contingency plans in the event of a severe disruption to supply or a supply outage. These plans were reviewed and updated on a regular basis.

Asked whether he was satisfied the industry was prepared for a pipeline failure McNaught said: "During a supply issue or outage, our key focus is to ensure that it is a safe operation and integrity and quality of the product is protected."