US President Joe Biden next week will announce support for the African Union's (AU's) admission to the G20 group of the world's largest economies as a permanent member, a White House official said on Friday.

Biden will make the announcement during the US-Africa Leaders Summit in Washington next week, White House adviser Judd Devermont said, when Biden will meet presidents of African countries.

"We need more African voices in international conversations that concern the global economy, democracy and governance, climate change, health, and security," Devermont said.

Devermont said the move, first reported by the Washington Post, comes after requests from African Union Chair and Senegalese President Macky Sall and South African President Cyril Ramaphosa.

South Africa is the only G20 member from Africa. The AU is made up of 55 member states.

"It’s past time Africa has permanent seats at the table in international organisations and initiatives," Devermont said, adding that the move builds on Washington's strategy for Sub-Saharan Africa.

The United States released a new strategy document for sub-Saharan Africa in August, stressing the region's importance, the threats posed by China and Russia, and vowing to extend defense cooperation with like-minded African countries.

Last year, US Secretary of State Antony Blinken said Washington would have to do things differently to help Africa with its infrastructure needs and it was time to stop treating the continent as a subject of geopolitics and rather as a major player on its own.

Africa needs billions of dollars a year for roads, railways, dams and power and in the last decade has received huge sums from China, which generally does not tie money to political or rights-related conditions.

Washington has characterised Chinese lending as predatory and leading to potential debt traps, and has focused on facilitating private investment, but officials acknowledge it needs to do more speed up assistance.

The Biden administration has been criticized by some as inattentive to Africa: a common complaint about US foreign policy but one that has rung louder since China deepened its political and economic roots on the continent.

But Biden has struck a different tone from former President Donald Trump, who disparaged some African nations and barred travel from six of them.