"Motorists will want to know why prices keep going up (other than the tax)," he says.
Stockdale says the fuel companies need to front up and show why prices have risen so much.
"As it is, the AA doesn't think the latest prices is justified – fuel company costs have not risen in the last few days, and the last price rise wasn't justified either."
He says if anything the fuel companies should be cutting prices as margins are now very high, the highest in over a year and well above average.
A Z spokeswoman said the latest change to the price at Z was due to high barrel price (over US$80) and a low Kiwi dollar (66 cents) - the same factors driving recent price change.
The cheapest price point on Z 91 across the country was at Whakatāne at 205.9, while the most expensive was at Z Queenstown at 247.9, she said.
Gull price analyst Rohan Mehta spoke to the Herald about how its company operated network was pricing 91 today, stressing that he could not speak for the 24 independent Gull sites.
"We have not lifted our prices across any of our company operated retail network – as always, we rely heavily on optimism and do not see the need to raise prices in the event of global oil price increase almost instantly," Mehta said.
The highest priced Gull sites across the country are around Auckland, which have reached these highs again due to the regional fuel tax which came into effect in July, Mehta said.
"In saying that these sites still sit comfortably around 9 cents below the highest recorded price as per today."
The newest Gull site in Glen Eden was offering the cheapest prices across the company's Auckland network selling regular 91 for $2.177 per litre, Mehta said.
But the lowest priced 91 Gull was offering was at $1.977 per litre – well below the $2.00 per litre mark, he said.
That was the price tag for motorists pumping fuel at the small village of Atiamuri, just north of Taupo.
Andrew McNaught, Lead Country Manager for Mobil, said a number of factors drove price including product costs, exchange rates, excise duties and taxes, transportation, retailing costs and local market competition.
"Setting retail prices is thus a balancing act between the immediate effects and influences of the market versus the longer-term outlook for our business and the industry," McNaught said.
"The recent changes in Mobil's retail fuel prices have been driven predominantly by a combination of increased product costs and fluctuating exchange rates, though they are still influenced by the other factors previously mentioned."
A regional fuel tax was introduced on July 1 and generated $13.2 million in its first month of operation – that was $700,000 more than initial estimates.
The price of diesel has soared to $1.809 in some South Island locations.
Next month a 3.5c a litre excise tax will be added nationwide. Including GST, the increase is expected to see 4c a litre added to petrol prices across the country.
