US President Barack Obama said Tuesday that it was time for the world to change its approach to Africa, as he made the first address to the African Union by a US leader.

"As Africa changes, I've called for the world to change its approach to Africa," Obama said in a speech at the AU's headquarters in Ethiopia's capital.

"A half century into this independence era, it is long past time to put aside old stereotypes of an Africa forever mired in poverty and conflict. The world must recognise Africa's extraordinary progress."