Fuel companies are warning of a potential shortage after Auckland Airport's pipeline near Marsden Point was shut down.

The line was closed as a precaution on Sunday after an alarm from a monitoring system sounded.

The 170km-long line has been running at reduced pressure since a crisis triggered when it ruptured in September near Marsden Point.

A Refining NZ spokesman says a series of checks throughout the day on Sunday had determined the pipeline was fit for service.

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But BP says fuel companies are still concerned about supply, saying fuel stocks are still recovering from September.

The Marsden Point to Auckland fuel pipeline - the sole source of jet fuel, petrol and diesel for the city - was restarted on Sunday evening.

Read more: Refining NZ's Marsden Point to Auckland fuel pipeline reopened after scare

The prospect of another oil shutdown in Auckland has prompted the Government to speed up an inquest into the city's supply options.

Prime Minister Jacinda Ardern on Monday said the weekend's scare was a sign a review of Auckland's fuel supply options and back-up plans now needed to be sped up, NZN reports.

"It was just another reminder of why we need to expedite that work, so we don't have the critical vulnerability" she told TVNZ.

She said Energy Minister Megan Woods was already looking into prioritising the inquiry.

"There needs to be alternatives so if we have to we have a situation where, even as we had yesterday, a false positive, that turns out to be some kind of crack or anything that results in a shutdown that we have a backup mechanism," Ardern said.

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"We just can't afford that kind of slowdown."

Customers of Refining New Zealand on Sunday received a notification that the pipeline, which carries fuel from Northland to storage tanks into South Auckland's Wiri, had been temporarily shut down after an alarm from the pipeline's monitoring system went off.

The alarm activated about 5.15am.

A Refining NZ spokesman said a series of checks throughout the day had determined that the pipeline was fit for service.

"Based on the information from our investigation we believe there was no leak, and at around 6pm this evening the decision was taken to restart the pipeline," he said.

Any significant disruption to aviation and road fuel supplies would have been a blow for airlines as they enter the peak holiday flying period and motorists ahead of the holiday driving season.

Read more: Airport fuel crisis - Kauri log digger damaged oil pipeline

Investigations in the September incident are continuing after a digger is thought to have caused damage some time before the pipeline broke, spewing aviation fuel into a swamp.

The government is still working on the framework for a likely inquiry.

A report prepared for the Ministry of Economic Development, which was subsumed into MBIE, found New Zealand's national fuel supply network was reasonably robust and adept at responding to most disruptions.

Read more: Marsden Point fuel pipeline shut down after leak-detection alarm
However, there was a risk to Auckland supply because the Marsden Point refinery supplies almost all of the city's fuel through the refinery-to-Auckland pipeline.

- Newstalk ZB