The financial viability of many countries is being threatened by unsustainable debt, India's Prime Minister Narendra Modi said on Friday, as he called for the Group of 20 (G20) to focus on the world's most vulnerable citizens.

Trust in international financial institutions has eroded, partly because the lenders had been slow to reform themselves, Modi said in a video message at the beginning of a two-day meeting of G20 finance ministers and central bank governors.

Group of 20 (G20) nations have some disagreements over restructuring debt for distressed economies, the chief of the International Monetary Fund (IMF) said on Saturday, adding that banning private cryptocurrencies should be an option.

India's G20 presidency comes as its South Asian neighbours Sri Lanka, Bangladesh and Pakistan are seeking urgent IMF funds due to an economic slowdown caused by the COVID-19 pandemic and the Russia-Ukraine war.

China, the world's largest bilateral creditor, urged the group of big economies on Friday to conduct a fair, objective and in-depth analysis of the causes of global debt issues as clamour grows for lenders to take a large haircut, or accept losses, on loans.

"On debt restructuring, while there are still some disagreements, we now have the global sovereign debt roundtable with consideration of all public and private creditors," IMF Managing Director Kristalina Georgieva told reporters after chairing the roundtable with Indian Finance Minister Nirmala Sitharaman.

"We just finished a session in which it was clear that there is a commitment to bridge differences for the benefit of countries."

U.S. Treasury Secretary Janet Yellen said there were no "deliverables" from the meeting, which was mostly organisational.

Further discussions of the panel, which includes major bilateral creditors including China, India and the G7 countries, several debtor countries, are planned around the time of the IMF and World Bank spring meetings in April.