Nigeria's candidate to head the World Trade Organization (WTO) said she feels "strong support" from Africa and expects African leaders to unite behind one candidate as sources following the race said she is gaining broader backing.

Ngozi Okonjo-Iweala, a former finance and foreign minister who has 25 years experience at the World Bank, is seeking to replace Brazil's Roberto Azevedo who announced last month he would step down on August 31, in a surprise move at a critical juncture for the body.

Africa has struggled in the past to unite behind one candidate and the Geneva-based watchdog has never been led by someone from the continent before, nor by a woman, and there is broad feeling it is Africa's turn.

"I cannot presume for any group but I can tell you that I feel strong support from the region," she told Reuters late on Monday, saying she was having "very constructive conversations" among the 164 members.

One delegate described her as "definitely the favourite", especially since European Trade Commissioner Phil Hogan dropped out, and likely to be acceptable to China and the United States.

On Tuesday Okonjo-Iweala told a Geneva briefing she wanted to raise Africa's share of world trade from the current 3 percent, though gave no target figure.

Asked how the WTO could help the world recover from the Covid-19 pandemic, she stressed the need to ensure any export restrictions were "temporary, transparent and proportionate so we make sure they do not harm other members".

FULL IN-TRAY

The new head's in-tray includes overseeing reforms, clinching a long-overdue multilateral trade deal and dealing with growing protectionism and US-China trade tensions as well as tackling the post-Covid-19 global recession.

"The problems are very deep and challenging but they are not insoluble," she said, stressing the need for reform including of the body's top court which is a priority for Washington.

Critics say she does not have enough direct trade experience but she says being an outsider is an advantage. Backers laud her negotiating skills, including a deal to cancel billions of dollars of Nigerian debt.

Nominations are open until July 8.