Days after drone attacks halved Saudi Arabia's oil output, petrol prices are jumping worldwide.
On Tuesday morning Gull confirmed wholesale international refined fuel prices in Singapore rose overnight.
Prices increased overnight by approximately US$6.50 per barrel (159 litres) for petrol, and US$5.50 per barrel for diesel.
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Taking the exchange rate into account, Gull says this increase works out to 6.5 NZ cents per litre for petrol, and 5.5 cents per litre for diesel.
It's the first trading day for the key Singapore market since the Saudi Arabia attack, which is believed to have taken out about 5 percent of the world's oil supply.
A small minority of New Zealand's petrol is imported from Singapore and South Korea.
General manager Dave Bodger says Gull is committed to not increasing prices at its company-controlled outlets before the end of the working week, giving Kiwi motorists three more days to take advantage of petrol prices before they go up.
"We will monitor the situation daily," Bodger says. "We appreciate that any price increase is a major blow for Kiwi motorists, and we will minimise and delay this as much as possible."
Economists have warned massive price hikes could be on the cards. New Zealand sources about a quarter of its annual foreign oil imports from the Middle East, and University of Otago international relations expert Robert Patman told Newshub that New Zealand is "likely to be affected in the not-too-distant future".
Kiwi economist Cameron Bagrie says a worst-case scenario would see prices skyrocket to $3 a litre.
"Saudi Arabia in regards to the oil industry around the globe is about as strategically important as Beaden Barrett is to the All Blacks or Steve Smith is to the Australian cricket team," he told the AM Show on Monday.
"It really matters. Saudi Arabia's 10 percent of global production... we're going to see oil prices move up sharply over the next couple of days."
US officials have blamed Iran for the weekend's drone strikes, but Iranian President Hassan Rouhani has laid the blame with a Yemeni group.