An urgent instruction has gone out to government departments ordering staff to cancel non-essential air travel as the fuel crisis continues to bite.

The Department of Prime Minister and Cabinet has issued the directive across the public service, meaning the ruptured fuel line near the Marsden Pt oil refinery is now affecting how government does its work.

Police and Corrections staff have also been told ensure vehicles are kept fully fuelled.

Ministry of Business, Innovation and Employment chief executive Carolyn Tremain confirmed a halt on air travel.

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"As part of the Government response to the fuel pipeline disruption, public servants are being asked to defer non-essential air travel in and out of Auckland.

"With the pressure on aviation fuel supplies, it is prudent the public sector does what it can to help the airlines and the fuel suppliers meet the challenges of the situation."

Ministry of Health executive director Jill Bond said focus had gone on air travel.

"We are working with our travel provider to identify which flights are still operating to Auckland and we are also encouraging staff to consider alternative arrangements where possible."

A Ministry of Social Development spokeswoman said it was working to reduce any non-essential travel.

Prime Minister Bill English confirmed government workers had been told to curb their travel.

"Which shouldn't be too difficult. You are looking here about a period of a week at most. They can do meetings by video and help accommodate the public by putting off travel."

Asked about his own campaign, English said most of his MPs were currently in their electorates and he had advised them not to do any unnecessary travel.

English said he would receive a full update on the fuel situation after arriving back in Wellington tonight.

This morning he met the chief executive of the Department of Prime Minister and Cabinet, the Acting Chief of Defence Force and the Acting Chief Executive of MBIE.

"We are taking the issue very seriously, we don't want travellers to be inconvenienced in this way...I'm advised around 70 per cent of previously scheduled flights are continuing."

English said work on restoring the pipeline was proceeding as planned and the deadline for completion was still sometime between Sunday afternoon and Tuesday afternoon of next week.

On some petrol stations running out of 95 petrol, English said there was no significant risk to fuel availability for trucks and cars - and certainly no reason for panic buying.

Asked if the event highlighted the vulnerability of New Zealand's infrastructure, English said work had been done to improve key infrastructure.

"We are getting good at dealing with this stuff, and I'm quite confident...the combination of efforts...most people will still be able to travel.

"Afterwards there will be a discussion, inevitably, about whether they have got the right amount of storage or need another pipe."

The fuel-pipe rupture is believed to have been caused by a digger working some months ago in farmland near Ruakaka.

Claw marks from a digger blade were found on the pipeline when it ruptured on Thursday when pressure in the pipe was increased to pump aviation fuel to Auckland.

The fuel pipeline is a critical link for getting fuel to Auckland and especially for Auckland Airport because there is no other way to transport jet fuel from the refinery south of Whangarei.

It has caused chaos at Auckland Airport with flights cancelled and airlines having to ration the amount of gas they can access.

It has also seen a handful of petrol stations in Auckland close some pumps selling 95 petrol although fuel companies say supply is not yet an issue.

It has come in the final week of the election campaign and seen the Government promise to throw all it can to help ease the pressure and get fuel to where is needed.

That has included government departments being told to review their travel plans.

The Prime Minister's department told the Herald the order is part of its "Odesc" response to the fuel crisis.

A police spokesman confirmed advice around flights had been received - and that police had responded to the developing crisis with a briefing to Auckland staff to keep vehicles fueled.

"It is always police best practice for operational vehicles to have at least half a tank of fuel in them, and that vehicles are filled at the end of every shift.

"Staff in Auckland were reminded of this on Saturday night after police were advised of the situation regarding aviation fuel supplies to Auckland."

Corrections national commissioner Terry Buffery said staff had been asked to restrict air travel - and to keep vehicles fueled.

"Corrections has been asked, along with other public sector agencies, to refrain from any non-essential air travel to Auckland. Deputy chief executives were immediately informed and took appropriate action.

"Additionally, Corrections has asked staff to ensure our Auckland based vehicles are filled with fuel as a precautionary measure."

Odesc, or the Officials' Committee for Domestic and External Security Coordination, is a high-powered group of public service leaders who gather at times of national crisis to make sure government response is coordinated and rapid.

It is chaired by department chief executive Andrew Kibblewhite with the chief executive of government department responding to the particular crisis generally leading the ODESC response - in this case, Tremain from MBIE.

The department spokeswoman said Odesc was convened "in terms of the national security system".

It met over the weekend as the impact of the fuel rupture became apparent.

The committee also convened to co-ordinate government crisis response after the 2015 terror attacks in Paris, for security for the Cricket World Cup, the 1080 contamination threat to milkpowder and the Ebola outbreak in 2014.