The Group of 20 –- which brings together the world's top economies including the US, China and some European nations -- is holding talks in hybrid format in the Indonesian capital Jakarta. 

Opening the two-day meeting, President Joko "Jokowi" Widodo warned of the risks to the fragile recovery from the crisis in Ukraine, where fears are growing that Russia is set to invade.

"This is not the time for rivalries and creating new tensions that disrupt the... recovery, let alone endanger the safety of the world, as is happening in Ukraine," said Jokowi, whose country currently holds the G20 presidency.

"All parties must stop the rivalry and tension."

He urged the G20, which includes Russia, to instead focus on "collaborating" to help boost the global economy.

The threat of a Russian invasion of its ex-Soviet neighbour presents a fresh challenge for a world already struggling to keep a recovery from the coronavirus pandemic on track as inflation surges.

Also on the agenda at the meeting -- originally due to take place on holiday island Bali before being moved due to an Omicron virus wave -- was how to reform global health systems to be better prepared for future pandemics.

'Mobilise funds'

US Treasury Secretary Janet Yellen, speaking via video-link, said that "we must act urgently to strengthen the global health architecture so that we have the tools to prevent, prepare for, and respond to future health crises".

The world's large economies "must also focus on mobilising the funding needed to address gaps in the system," she said, quoted by AFP.

Calls have been growing for new funding systems, especially following the challenges in producing and distributing Covid vaccines.

Financing needs are "undeniable", with estimates of the amount required running to $75 billion over the next five years, Yellen said.

Britain's Finance Minister Rishi Sunak, who was also taking part remotely, said a full global economic recovery "will not be possible until we achieve our immediate priority of getting vaccines from airports to arms".

His Indonesian counterpart Sri Mulyani Indrawati said the G20 was discussing establishing a fund to combat future health crises, which would be coordinated by the World Health Organization.

Efforts to strengthen the global health architecture can only succeed if they bolster the WHO's role, the body's chief Tedros Adhanom Ghebreyesus stressed.

"It's clear that at the centre of this architecture, the world needs a strong and sustainably financed WHO... with its unique mandate, unique technical expertise and unique global legitimacy," Tedros told the talks.

Sunak also called for international cooperation to strengthen supply chain and energy market resilience.

"As we know, high energy prices and disruptions to our global supply chains have caused real challenges in many of our economies," he said.

"It is critical that we, together, work to promote the resilience of energy markets and supply chains to future shocks while remaining committed to openness."

Another key topic was skyrocketing global inflation, and how central banks in developed nations proceed with hiking rates and withdrawing massive pandemic stimulus without causing shocks in developing countries.

Withdrawing stimulus will "potentially create tighter global financial conditions and may induce capital outflows from emerging markets," warned Perry Warjiyo, governor of the Indonesian central bank.

Yellen also urged G20 members to back a proposed fund to invest in pandemic prevention and preparedness, warning that failure to close gaps in global health systems could result in "devastating" costs.

Yellen said that the new financial intermediary fund - to be hosted at the World Bank - would help channel the estimated $75 billion in investments needed to reduce global vulnerabilities to future pandemics.

"While the human and economic trauma of the (COVID-19) pandemic is fresh in our minds, we have a political window to act to address the deficiencies in our global health architecture," she said, according to a text of her prepared remarks, quoted by Reuters. "The cost of not doing so could be devastating."

In the remarks to be delivered remotely at the meeting hosted by Indonesia, Yellen sought to dispel reservations raised by some G20 countries about the proposed fund, arguing that it would not siphon off funds needed to strengthen the World Health Organization, or create a new multilateral organization.