Fatih Birol of the international energy watchdog also called on countries to reduce demand for energy by encouraging people to work from home and get more consumers to use public transport.
Mr Birol said politicians and markets were still underestimating the scale of the crisis.
He said it could take six months or longer to fully restore oil and gas flows from the Gulf.
The conflict was “the greatest global energy security threat in history”, he told the ‘Financial Times’.
The Paris-based International Energy Agency is an intergovernmental organisation, providing data, policy analysis and recommendations to ensure secure, affordable, and sustainable energy.
Attacks by the US and Isreal on Iran have prompted a fierce response that has resulted in the loss of one-fifth of the world’s oil and gas.
Brent crude oil is now at $108, up from $72 before the outbreak of the conflict.
Mr Birol said the volume of gas that has been cut off by the fighting is twice as much as Europe lost from Russia in 2022 after that country invaded Ukraine.
More oil has been lost, he said, than during the twin shocks of the 1970s that triggered recessions and fuel rationing around the world.
As diesel prices hit €2.30 a litre in this country, the International Energy Agency (IEA) called on governments to encourage people to work from home where possible.
It said this would displace oil use from commuting, particularly where jobs are suitable for remote work.
The IEA said speed limits on motorways should be reduced by at least 10km an hour, as lower speeds reduce fuel use for passenger cars, vans and trucks.
Governments should also encourage a shift from private cars to buses and trains as this can quickly reduce oil demand.
It recommended alternate private car access to roads in large cities on different days.
Another measure recommended to reduce energy demand is an increase car sharing and drivers adopting efficient driving practices.
The IEA said efficient driving for road commercial vehicles and delivery of goods can cut diesel use.
People were also called on to avoid air travel where alternative options exist. The IEA said reducing business flights can quickly ease pressure on jet fuel markets.
Electricity bills could rise by €800 in fall-out from Middle East gas plants attacks
The energy agency said encouraging electric cooking and other modern options can reduce reliance on natural gas.
Governments were advised to encourage companies to implement short-term efficiency and maintenance measures.
The oil and gas markets were badly impacted this week after Israel and Iran fired waves of missiles at vital energy hubs in the Gulf, including the South Pars gasfield and Qatar’s immense Ras Laffan complex.
Mr Birol said politicians and markets were still underestimating the scale of the crisis.
The problem would grow bigger every day that flows of energy from the Middle East, which exports one-fifth of the world’s oil and gas, were trapped by Iran’s de facto blockade of the Strait of Hormuz.
“People understand that this is a major challenge, but I am not sure that the depth and the consequences of the situation are well understood,” he said in an interview.
The IEA’s 10 ‘immediate actions to reduce demand’:
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