The Bord Gáis energy index, which looks at wholesale energy prices around the world, recorded a 4% increase in July from June as all four commodities - oil, gas, coal and electricity - rose during the month.

The energy index stood at 141 in July, down 2% on the same month last year.

Brent crude oil prices rose by 3% last month due a fall in US crude stocks, which led to the benchmark US oil price hitting a monthly high of $109.32 a barrel - its highest level since the height of the tensions between the West and Iran in February 2012.

Strikes in Libya and falling production in Iraq and Nigeria also helped push prices upwards, as did tensions in Egypt.

The average day ahead gas price for July rose by 6% in July from June despite low demand levels. Bord Gáis noted heightened sensitivity to UK gas supplies in July as planned and unplanned maintenance of fields and terminals created a general ''tightness'' in the market.

The coal element of the index saw a small rise as mine and port workers at the Colombian operations of US-based thermal coal miner Drummond started an indefinite strike due to a row over wages and benefits.

The monthly average Irish wholesale electricity price rose 7% month on month as a result of the 6% increase in the UK average wholesale gas price. The volume of electricity produced by wind turbines also fell due to the exceptionally warm and stable climatic weather conditions seen in July.

Bord Gáis noted that wind generated electricity met 5% of the country's electrical needs in July - the lowest monthly level so far this year and down from the 10% generated in June.

John Heffernan, a power trader at Bord Gáis, said that the movements in the index last month were surprising.

''The events of last winter, when gas supply concerns were raised following the depletion of storage levels amid the prolonged cold snap, seem to be lingering in the memories of traders,'' Mr Heffernan said.

He said that despite the influence of increasing levels of shale oil and the apparent deceleration of emerging economies, particularly China, crude oil prices rose following supply concerns, depleting stocks and buoyant investors.

''European coal prices received a boost on the news of another miner’s strike in Colombia which will reduce supplies. However, euro zone buyers did benefit from favourable foreign exchange rate moves which took some of the edge off July’s price rises,'' he added.