Petrol prices are expected to drop further before Christmas as the price of oil continues the slide started in June, with no let-up in sight.
Craigs Investment Partners broker Peter McIntyre expected West Texas crude prices to fall below $US60 ($NZ77.12) a barrel after Opec decided to maintain oil output, sending crude prices crashing to five-year lows.
''We haven't seen this sort of pull-back in prices since the 2008 global financial crisis. Prices have fallen 40 per cent since June and I expect the $US60 price to be tested.''
Z Energy cut its fuel prices by 3 cents per litre on all grades yesterday, the ninth consecutive drop in two months. Prices were getting close to $2 with 91 fuel at $2.03 a litre.
Motorists are now paying the lowest petrol prices since July 2012 and the lowest diesel prices since December 2010.
Mr McIntyre expected prices to be at or below $2 a litre by Christmas, adding some discretionary spending to consumers paying less to fill their tanks.
There were several factors for the falling oil price but one of the main points was the United States becoming more self-sufficient for oil due to its increased fracking (hydraulic fracturing).
Several members of Opec had pushed for a cut in production to boost the price. But Saudi Arabia, the largest producer in the oil cartel, favoured maintaining production at its current level.
Saudi Arabia and Opec would no longer be the mechanism to balance the market. They had relinquished the role, he said.
''Instead, the market itself - prices, in other words - will be the mechanism to rebalance the market. We cannot overstate what a dramatic and fundamental change this is for the oil market.''
However, overseas analysts predicted Opec would continue to flood the globe with oil in an effort to bury the US shale producers, Mr McIntyre said.
Other factors for the falling prices, apart from the US needing to buy less oil on international markets, was China's growth sinking to its lowest mark for 40 years and mounting concerns about slow growth in Europe.
''There's a general lack of demand for oil.''
There were good and bad points to the falling oil price, he said.
Among the good points were the benefits felt by consumers.
The extra money people had in their pockets from falling petrol prices would flow through to beleaguered retailers, particularly at this time of the year.
However, if prices remained at current levels, or fell lower in the next year to 18 months, inflation would start becoming a concern as people continued to spend.
That would mean higher interest rates, Mr McIntyre said.
Globally, falling oil prices and deflation risks in Europe were exerting downward pressure on bond yields.
US 10-year bond yields had edged below 2.2 per cent, with markets pondering the potential for yields to re-test 2 per cent - a level last reached in the mid-October ''flash crash''.
The risk of deflation was the focus for many in markets, particularly given the latest euro zone consumer price inflation release showing annual inflation of just 0.3% for the year to November.
The European Central Bank had already indicated it would look to increase the size of its balance sheet by 1 trillion ($NZ1.6 trillion), and Mr McIntyre expected the central bank would announce a broad-based asset purchase programme over coming months.