Cook onion, celery and garlic in oil in large saucepan over medium heat, 5 minutes, or until onion is tender, stirring occasionally.
Add sweet potatoes, curry powder and ginger; stir well. Add broth and bring to boil over high heat. Reduce heat and simmer about 30 minutes.
Puree mixture in blender. Return soup to pot and stir in coconut milk over low heat (Do not boil). Season with salt and pepper to taste and serve hot.