Lower energy use in the United States and ongoing redundancies helped push oil prices below $US34 ($NZ63.60) a barrel yesterday, close to a five-year low.
That would normally indicate a fall in pump prices for petrol but the lower New Zealand dollar might see oil companies holding back from a reduction.
Pump prices rose in the US yesterday, but by less than US0.008c a gallon.
Opec has cut its production in an effort to hold up prices but demand expectations for 2009 continue to fall.
"The bull oil era is officially over," Alaron Trading Corp analyst Phil Flynn said.
An oil industry report out yesterday showed that for all of last year, US petroleum deliveries - a measure of demand - fell 6% to 19.4 million barrels a day.
That trend appeared to be continuing this year with millions of US workers out of work and redundancies continuing.
Opec lowered its energy demand forecast for 2009 with investors already shrugging off production cuts of 4.2 million barrels a day by member countries.
Opec said in its January report that it expected world demand for crude would fall 180,000 barrels per day this year compared with the previous year.
US oil stocks have been rising for months.
The Energy Information Administration said crude inventories grew 1.2 million barrels in the week ended yesterday, after jumping 6.7 million barrels the previous week.
