"It's development in reverse," Alexander De Croo told AFP on the sidelines of a G7 development meeting in Paris.

"It took decades to build stable societies, to develop local economies, and it took only several weeks of war to destroy that," he added.

"We did a study after six weeks of war and estimated that even if the conflict ended at that point, 32 million people would be pushed into precarity in 160 countries," said De Croo.

The war has led to closure of the Strait of Hormuz, through which a fifth of the world's oil and liquefied natural gas flows in peacetime.

Gulf nations are also important for many oil products and feedstocks to make fertiliser.

A shortage of supplies and high prices has led to countries in Africa and Asia imposing a range of measures that include fuel rationing and shortening the work week to reduce consumption. Other countries have reduced fuel taxes to cushion the impact on consumers.

The UNDP says the war will have a profound impact on Sub-Saharan African countries as well as certain countries in Asia such as Bangladesh and Cambodia.

Developing island nations will also be particularly hard hit.

High "energy costs, a lack of fertiliser, will have an enormous impact in the months to come" on people in these countries, said De Croo, a former prime minister of Belgium.

He also warned of "political instability and a drop in remittances from abroad because a lot of people working in the Gulf countries send money home".

To avoid poverty taking hold, the UNDP estimates that around $6bn "is needed in subsidies to support those most vulnerable to high food and energy prices", he added.

De Croo said discussions were already underway within the IMF and World Bank.

"You can say that six billion dollars is a lot -- the war cost nine billion dollars per week," he added.

The crisis comes as development aid is at a historic low, having dropped by more than 23 percent last year, primarily due to cuts by major donors led by the United States.