Some grades of petrol are running out in Auckland following disruption to supplies at the weekend.

Some Z stations have run out of petrol at stations from Pt Chevalier to Clevedon today. BP and Mobil say outages at their sites will also be minimal and short-lived.

A Z spokesman, Jonathan Hill, said there would be sporadic ''stock outs'' which could run into next week following the shut down of the fuel pipeline that runs from Marsden Point refinery to Auckland.

What turned out to be a false alarm meant fuel flow was stopped in the 170km pipeline for more than 12 hours on Sunday.

There were already lower supplies following the rupture of the Refining NZ pipeline at Ruakaka in September.

The pipeline has been operating at 80 per cent capacity since then and it could be early next year until it was fully restored.

Hill said this came as demand for aviation fuel was higher than anticipated in November and December.

He said the fuel industry made a decision to prioritise the aviation sector and pump more aviation fuel since the shutdown on Sunday to avoid any of the widespread disruption that hit airlines in September.

"All of this has had the affect of stretching the supply line and we've been sucking fuel in a fairly conservative way since September. But with jet fuel demand going up quite strongly it's sharpened the effect."

He said some grades of petrol could run out at some stations but typically for no more than six hours until a truck can make a delivery. There was more trucking of fuel from ports such as Tauranga.

While it could take several days to rebuild stocks, motorists shouldn't be worried about filling up for their holidays.

"I don't think there's any reason for motorists to be concerned about fuel supplies in the lead up to Christmas. There's plenty of fuel in the country," Hill said.

Mobil's country manager Andrew McNaught said his company was focused on minimising disruption.

''We are assessing the potential impact on supplies to Mobil service stations as a result of this issue and working to put alternative supply arrangements in place to minimise any impacts on our customers,'' he said.

''This includes arranging additional trucking of fuel from other terminals to provide additional deliveries into the region,'' he said.

BP New Zealand managing director Debi Boffa said her company was also trucking more fuel in to Auckland.

Yesterday Prime Minister Jacinda Ardern said she was concerned about the state of the vulnerability of the supply network.