The European Union (EU) is backing former Nigerian finance minister Ngozi Okonjo-Iweala to head the World Trade Organization (WTO), sending a signal of trust in Africa, an EU official said on Monday.

Okonjo-Iweala and South Korean trade minister Yoo Myung-hee are vying to be the first female leader in the WTO's 25-year history, replacing Brazilian Roberto Azevedo, who quit a year earlier than expected at the end of August.

The EU's support for Okonjo-Iweala is considered a strong signal to reinforce the multilateral order and a sign of mutual trust between the bloc and Africa, the official said.

The WTO faces dual challenges: criticism from US President Donald Trump's administration which froze its appeals body by blocking its appointment of judges, and worsening US-China trade relations.

Okonjo-Iweala, 66, a previous Nigerian foreign minister, is an economist and development specialist serving as board chair of global vaccine alliance Gavi. She wants the WTO to help poorer countries access Covid-19 drugs and vaccines.