Volatility remains the only certainty but the strength of the New Zealand dollar against the greenback will be a key driver of pump prices.
Both BP and Shell said they had held off putting prices up during the holiday period, but both rose 4c per litre for petrol and 2c for diesel on Tuesday, to respectively $1.69.9 for 91 octane petrol and $1.09.9 for diesel, with BP saying another rise is likely.
BP spokeswoman Diana Stretch said Tuesday's 4c price hike did not cover a 12% increase in costs reflected in refined Singaporean products, where New Zealand fuel is sourced.
"Another rise is likely in the not-too-distant future.
"We did not pass on the full 12% [Singaporean] rise.
"We held off putting the price up since before Christmas to give motorists a break during the holidays," she said yesterday.
She highlighted the difficulty in predicting prices given the 2009 volatility when Singaporean refined barrel prices swung between $US43 up to $US90 and the New Zealand dollar fluctuated between about US50c to more than US70c - the latter dampening what could have been higher pump prices.
Crude oil hit a record $US147 per barrel in July 2008, which in turn saw record New Zealand pump prices up to $2.20 per litre.
Westpac chief economist Brendan O'Donovan believed there was still 3c of "fat" in the present pricing regime for the petrol companies, with Dubai crude yesterday at $US79 per barrel and the US73.3 exchange rate equating to $1.63 per litre.
"There's still a touch of fat in the system for the petrol companies to absorb upside [increasing] oil prices," Mr O'Donovan said.
He said growth in the economies of the United Kingdom, Europe and Japan was expected to "disappoint" and the US to be a "surprise, positive".
However, the "strong growth" of emerging economies such as China and India would increase crude oil demand and push up prices during the year ahead.
The Daily Telegraph in Australia reported petrol prices are tipped to rise by up to 6c per litre during the next two weeks as the global financial crisis softened.
The price Australian companies paid for their petrol had recently risen by 6c per litre to $1.18 - a four-month high - which had not yet been passed on to motorists, but "very likely would be in the coming days", CommSec chief economist Craig James said.
Australian petrol cost around $A1.20 a litre during last year as the financial crisis drove down demand, but a price of $A1.30 to $A1.35 was more likely for 2010, he said.
Shell spokeswoman Jackie Maitland said yesterday international crude oil prices during the past fortnight had risen between $US4-$US5 per barrel and had subsequently eroded profit margins.
"Margins did fall during the Christmas period.
"We hoped to give people a break during the travelling [holiday] period," she said yesterday.
Shell and BP's last increase was on December 3 and on December 11 petrol prices fell again, by 3c.
The Automobile Association have a policy of not speculating on future petrol prices, so as not to influence decisions, but communications manager Simon Lambourne said yesterday this week's 4c petrol and 2c diesel rises "were not unreasonable or unexpected".
"We understand margins were down and costs up.
"We're happy they held off raising prices during the holiday driving season," he said.
