Key Points:

Forget talk of petrol creeping towards $2 a litre - many Kiwi motorists are paying it already.

Motorists filling up at G.A.S in Omapere, Northland, on Friday were paying $2.099 for 96 fuel and $2.085 for 91. Fill up 20 minutes down the road at Shell Kaikohe, and your bill drops by 20c a litre, to $1.819 for 91 octane.

G.A.S. Omapere owner Shane Lloydd told the Herald on Sunday times were tough for business owners in the Hokianga, with fewer day or weekend trippers from Auckland due to the cost increase.

He said he had to price high to stay open and he lacked the bulk buying power of the big companies.

"It's out of our hands I'm afraid. The city boys buy in bulk and have huge holding tanks, but we don't. Rural areas are really getting hammered, all around the country."

When the Herald on Sunday visited the station, local Margaret Walters was filling up for the long trip south to Auckland to visit her son.

She spent $30 on almost 15 litres of 91 and, while acknowledging prices were steep, said it was "important to support local enterprise".

Nevertheless, the AA reminded drivers to check advertised prices before lifting the nozzle.

Motoring affairs general manager Mike Noon said individually owned sites set their own prices but motorists should be able to expect fair margins.

Sometimes lack of competition in a remote location, rather than extra freighting costs, could see overpricing at smaller sites. "They can charge whatever they like."

There were often genuine reasons for regional pricing variations, including whether the site owned its tanks and if a third party sourced the fuel.

Motorists are also being hit hard in the remote south and in several of the country's more remote locations.

Fox Glacier Motors was last week charging $2.03 for a litre of 95 octane fuel, $1.96 for 91 and $1.53 for diesel.

Prices reached the $2 mark about a week ago, an employee said.

Fuel on Waiheke Island was also pricey last week, with BP Oneroa charging $1.979 for 95, $1.929 for 91 and $1.519 for diesel.

The manager said the next price hike would likely take it over the $2 mark. He said it was just as expensive to get fuel to Waiheke as it was to get it to Haast, on the southwest coast of the South Island, because the fuel needed its own barge "which is very, very, expensive".

Not quite as expensive as hauling it to Stewart Island, however, where the current price of $2.06 for a litre of 91 is high, but nowhere near last year's $2.18.

Things are even worse in the Chathams. A shop attendant at Waitangi Hardware quoted $2.30 for a litre for 91 and $1.80 for diesel, and said locals had been paying more than $2 a litre for at least six months.

At the other end of the scale, drivers in Hamilton should head to Gull's Norton Rd site. General manager Dave Bodger said prices were sitting at $176.9 for 91 and 133.9 for diesel on Thursday.

While the oil companies refused to predict when the next price rise would hit, Noon said forecasts looked "quite concerning for motorists".

Other factors, such as carbon emission schemes or a regional fuel tax, were expected to send petrol prices even further north. Biofuel additives to petrol could knock the price up as much as 7c a litre, he said.

Last week's round of price rises was kicked off by BP on Tuesday. It raised its price per litre to $1.79.9 for 91 and $1.85.9 for premium, with Caltex following suit soon after.

BP spokeswoman Diana Stretch said half of its 280 New Zealand stations were owner-operated, meaning each owner set their own pump price. These were generally in more rural areas, she said, where delivery costs could push up the price.

She said none of the sites where the price was set by BP had yet tipped the $2 mark.