Recent easing in the value of the Australian dollar has not yet been reflected in diesel fuel prices, although a cooling in political unrest in the Middle East and weakening demand for energy products in China could see pump and wholesale prices soften a little, energy sector sources say.

International oil prices have remained unusually stable in recent months, declining only marginally despite US President Barack Obama’s recent jobs creation plan announcement and a deepening in international concerns about the Greek and Italian debt crisis.

The Australian Institute of Petroleum report for the week ending Sunday, August 18, shows a national average retail diesel price in rural and regional (non-metropolitan) areas of Australia of 149.9c/litre. That’s identical to the figure published in Beef Central's corresponding report last month.

Prices remained fairly stable across state and territory regional/country areas over the past four weeks, after some earlier fluctuation in the market.

At a state-by-state level, non-metropolitan regional diesel prices in this week's report included:

• Victoria 145.6c/l (0.1c down on last month)
• NSW 150.6c  (up 0.1c on August)
• Qld 149.3c (down 0.1c)
• WA 152.6 (up 0.5c)
• SA 150.1c (down 0.6c)
• TAS 152.8c (down 0.5c), and
• NT 168.2c (up 0.1c).

As the accompanying graph shows, national prices reached a high-point around 157c/l in early April, before beginning to ease in early May around the time the A$ value softened off extreme levels above US109c and the second wave of concern about the global economy started to emerge.

Since then, prices have moved surprisingly little.

Crude oil, diesel and petrol prices are closely linked, as the price of crude oil accounts for the vast majority of the cost of producing a litre of petrol or diesel, the Australian Institute of Petroleum says. Crude oil is purchased in US dollars, meaning that changes in the value of the A$ against the US$ have a direct impact on the relative price of crude oil in A$ terms.

The big rise in regional prices evident in the graph started around the end of February, when retail diesel was worth around 140c/l – still 6.4pc percent below where prices currently sit.

Today's price is still more than 12pc above the low-point in the market at the start of December last year.

The AIP national regional average price is calculated as a weighted average of retail diesel fuel prices for non-metropolitan and country regions in each State/Territory, where the weighting is based on the number of vehicles using diesel fuel. All values are in cents per litre and include GST.

• Click on the image here for a better view of recent regional Australian diesel price trends.