A number of finance ministers skipped a gathering of the Group of 20 top economies in South Africa on Wednesday, and other top officials curtailed trips to a meeting marred by disputes over the main issues of climate, debt and inequality.

Agreeing on a declaration has always been tough for a gathering that includes China, Russia, the European Union and the United States. But differences are starker than ever and some finance ministers were too consumed with domestic politics to show up for the two-day meeting in Cape Town.

Finance ministers from many of the G20's biggest economies - the US, China, Japan, India and Canada - cancelled their attendance of the event, which is meant to bring them and central bankers together to discuss global economic challenges. The EU's senior economic official also stayed away.

Their absences reduced what was already a small chance of agreeing on a communique. There also seemed little hope of accord on issues that the host, South African President Cyril Ramaphosa, sees as key: scant climate finance from rich nations, reform of a financial system that penalises poor countries and widening inequalities.

"At this time of global uncertainty and escalating tension, it is now more important than ever that the members of the G20 work together," he said in his opening remarks.

"The erosion of multilateralism presents a threat to global growth and stability."

South Africa's central bank governor, Lesetja Kganyago, said a number of recent G20 meetings had finished without agreement on a communique and that the fact that some countries were being represented by deputy ministers was not a problem.

"There is no one in the room then saying ... 'I'm going to make this point, but I think I am too junior so they might ignore it'," he told Reuters.

Alex van den Heever, political scientist at the University of the Witwatersrand in Johannesburg, said the absence of the United States from G20 talks - it also declined to send its top diplomat to a meeting of G20 foreign ministers last week - "makes it very difficult to see how people will move forward".

CLIMATE WOES
South Africa had hoped to make the G20 a platform for putting pressure on rich countries to do more to tackle climate change, and to give more towards poorer countries' transitions to green energy and adaptation to worsening weather.

"Those most responsible for climate change have a duty ... to support those least responsible," Ramaphosa said last week.

Energy Minister Kgosientsho Ramokgopa told Reuters on Tuesday that "what the American presidency does, effectively, is reconfigure the conversation (on green energy by) ... reintroducing elements we thought were resolved".

"Where it leads is anyone's guess," he said, adding that some countries might reconsider the scale and pace of their transition from fossil fuels to green energy as a result.

Some analysts said the retreat of the G20's biggest economy from the discussions raised questions about its relevance. Others saw an opportunity for moving ahead without the US.

"There could very well be synergies between large portions of what's left by excluding the US on particular issues," said Daniel Silke, director of the Political Futures Consultancy.

"It's an opportunity for South Africa to take its leadership role."