G20 finance ministers will meet Wednesday in Brazil, seeking ways to shore up a global economy whose nascent recovery is threatened by a raft of conflicts and crises, including the wars in Ukraine and Gaza.

The Ukraine war could take center stage at the meeting, with G7 countries due to meet on the sidelines to discuss shoring up Western support against Russia's invasion -- including what US Treasury Secretary Janet Yellen called an "urgent" proposal to use frozen Russian assets to increase aid for Kyiv.

Yellen, French Finance Minister Bruno Le Maire, IMF chief Kristalina Georgieva and other top economic policy-makers will gather in Sao Paulo for the two-day meeting -- though there will be some notable absences, including the British, Chinese, Indian and Russian finance ministers, organizers told AFP.

Brazilian Finance Minister Fernando Haddad, the host, will address the meeting by video conference, after coming down with Covid-19, organizers said.

The economic risks posed by the cost-of-living crisis, climate change and the conflict in the Middle East will also be on the agenda as finance ministers and central bank chiefs from the Group of 20 leading economies hold their first meeting of the year.

Brazil, which took over the rotating G20 presidency from India in December, also wants to use the two-day meeting to pressure for progress on fighting poverty, alleviating low-income nations' crushing debt burdens, and giving developing countries more say at institutions like the International Monetary Fund and World Bank.

International taxation also features on the agenda, amid global wrangling on how to deal with a so-called "race to the bottom" where some countries woo corporations and the super-rich with ultra-low tax rates.

The meeting, which follows one by foreign ministers in Rio de Janeiro last week, will start laying the economic policy groundwork for the annual G20 leaders' summit, to be held in Rio in November.

"There are a lot of issues on the table, and we face challenges on all of them," said the Brazilian official coordinating the G20 finance meetings, Tatiana Rosito.

"Our aim is to seek consensus and propose issues for dialogue," she told AFP. "What we're doing is setting the tone for dialogue and looking to build progress together."

- G7 targets Russian assets -

Finance ministers from the Group of Seven countries -- Britain, Canada, France, Germany, Italy, Japan and the United States, plus the European Union -- are due to hold a separate meeting Wednesday on renewing Western support for Ukraine, which is desperate for more aid to fend off Russia.

The G7 looks close to announcing plans to jointly set up a fund for Ukraine using profits generated by an estimated $397 billion in Russian assets frozen by the West over Moscow's invasion.

Ukraine has warned it is in dire need of more military and financial assistance, with a fresh $60 billion US package stalled in Congress.

Momentum appears to be building for Western plans to tap Russia's frozen assets: Yellen touted the idea, Canadian Deputy Prime Minister Chrystia Freeland said she agreed "100 percent," and British Prime Minister Rishi Sunak called to first seize interest from the assets, and then the assets themselves.

Founded in 1999, the G20 accounts for more than 80 percent of global gross domestic product (GDP), three-quarters of world trade, and two-thirds of the world's population.

In reality, it has 21 members: 19 of the world's biggest economies -- including both industrialized nations and emerging powers -- plus the European Union and, participating as a member for the first time this year, the African Union.