The global economy has withstood the strains of the Iran war better than first feared but its outlook is “heavily dependent” on a lasting resolution to the conflict, the Organisation for Economic Co-operation and Development (OECD) has warned.

In its interim economic outlook, the Paris-based body suggested global growth had been more resilient than expected when the US-Israeli war on Iran began in late February.

The OECD on Wednesday pointed to the release of global oil stockpiles, a sharp decline in energy imports by China and the switch to other fuels including coal as factors helping to cushion the economic impact of limited Gulf oil supplies.

However, it warned that the recent resurgence in oil and gas prices posed risks for the coming months. “Global economic prospects remain heavily dependent on whether a durable resolution to the Middle East conflict is achieved,” it said.

Presenting the forecasts, the OECD’s secretary general, Mathias Cormann, said: “The global economy has weathered another shock better than expected. But its capacity to absorb shocks is not unlimited. Energy inventories have fallen. Fiscal space is shrinking. Financing costs are rising and resilience alone is not enough.”

Cormann also highlighted the risks of rising government debt servicing costs as yields, or interest rates, rise across major economies.

“Fiscal and financial risks have grown. Thirty-year government bond yields are at their highest in 15 years or more in six of the G7 economies. That means higher debt-servicing costs for governments whose budgets are already under strain, and it means higher borrowing costs for businesses and households,” he said.

That echoed a warning by the managing director of the International Monetary Fund, Kristalina Georgieva, who told the BBC the world’s advanced economies must take action to reduce their borrowing and bring down debt levels.

Georgieva said a succession of global economic shocks had been “pushing debt levels up like a staircase not to heaven” with governments taking “no action to contain that service cost. [It’s] time to take that action,” Georgieva said, adding that courage was needed by politicians to take the necessary steps.

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In its quarterly forecast update, the OECD said it expected global economic growth to be 2.9% this year – a modest 0.1 percentage point upgrade from the 2.8% it forecast in June. At the same time it has trimmed the outlook for next year slightly, from 3.1%, to 3%.

Oil prices fell back below $100 (£75) a barrel on Tuesday amid hopes of a potential agreement between the US and Iran, but the continued standoff between the two sides has sent energy costs soaring in recent weeks.

The OECD warned that while more oil supplies were expected to resume as hostilities eased, “renewed or more persistent disruptions could result in both higher inflation and weaker growth”.

It also identified the record-breaking El Niño weather system – expected to be the strongest in 1,000 years – as a “significant downside risk” to the global economy, warning that it could hit agricultural production and push up food prices.

Looking at the UK, the OECD has significantly cut its inflation forecast for this year, from 3.7% to 3.1%, after prices rose less dramatically than expected.

Economic growth for the UK is forecast at 1.1% for 2026, up from the 0.9% it had forecast in June and 0.7% in March, “with consumption expected to be supported by newly announced government support measures”.

Growth is still expected to be weaker than the 1.4% reported last year and is forecast to dip slightly next year, at 1% – down from the 1.1% forecast in June.

In response, the chief secretary to the Treasury, Emma Reynolds, said: “Despite unprecedented pressures and conflict in both the Middle East and in Europe, the UK economy is showing strong resilience. We will face these challenges together and we are already giving families space to breathe.”