UN Secretary-General Antonio Guterres on Saturday slammed the world's rich countries and energy giants for throttling poor nations with "predatory" interest rates and crippling fuel prices.

Speaking in the Qatari capital, Doha, Guterres told leaders of more than 40 of the most deprived states that wealthy nations should provide $500 billion a year to help others "trapped in vicious cycles" that block efforts to boost economies and vital services.

The summit of Least Developed Countries (LDC) is normally held every 10 years but has twice been delayed since 2021 because of the coronavirus pandemic.

Afghanistan and Myanmar, two of the poorest countries, are not present at the Doha meeting of 46 LDC states because their governments are not recognised by UN members.

No leader from any of the world's major economies attended.

At a leaders' summit ahead of the start of the general LDC conference on Sunday, Guterres hit out straight away at the way poor nations are treated by the more powerful.

"Economic development is challenging when countries are starved for resources, drowning in debt, and still struggling with the historic injustice of an unequal Covid-19 response," he said.

The LDCs have complained that they did not get a fair share of the Covid vaccines that went mainly to Europe and North America.

"Combatting climate catastrophe that you did nothing to cause is challenging when the cost of capital is sky-high" and the financial help received "is a drop in the bucket", said Guterres.

"Fossil fuel giants are raking in huge profits, while millions in your countries cannot put food on the table."

Guterres said the poorest nations were being left behind in the "digital revolution" and the Ukraine war had fuelled their food and fuel prices.

"Our global financial system was designed by wealthy countries, largely to their benefit," he said.

"Deprived of liquidity, many of you are locked out of capital markets by predatory interest rates," the UN leader said.

A host of presidents and ministers hit out at financing conditions for LDCs, whose debt has more than quadrupled in a decade to an estimated $50 billion in 2021.

East Timor's President Jose Ramos-Horta called interest rates "rapacious" and "insensitive".

Malawi's President Lazarus Chakwera, the summit chairman, highlighted "broken promises" and said that aid was not "an act of charity" but a "moral responsibility".

Wealthy nations had failed to keep a promise to give 0.15-0.20 percent of their Gross National Income to LDCs, the UN chief said.

With poorer states trapped in a "perfect storm for perpetuating poverty and injustice", Guterres said LDCs required a "minimum" $500 billion a year to overcome their problems, build up job creating industries and repay debts.

He added that the United Nations would also "keep pushing" richer countries to hand over hundreds of billions of dollars promised separately to help poorer states battle climate change.

Under proposals a so-called Doha Programme of Action, a food stockholding system, will be set up to help countries facing hunger crises through drought and high prices.

It also calls for new efforts to help LDCs attract foreign funding and lower interest rates to ease the impact of their debts.

Bhutan will this year become one of seven countries -- along with Bangladesh, Laos, Nepal, Angola, Sao Tome and Principe and the Solomon Islands to "graduate" out of LDC status by 2026.

But they will gradually lose trade and aid privileges. Guterres said they risk becoming "victims of the cruelest sleight-of-hand trick -- support systems vanishing before their eyes" and would need help after they move up the wealth scale.