Heat the oil in a large saucepan. Add the ginger, garlic, bay leaves, chilies, turmeric and black pepper. Season with salt and cook over medium heat, stirring occasionally, about 5 minutes.
Add the stock, potatoes and carrots and bring to a boil. Lower the heat and cook for 15 minutes, covered, until the potatoes and carrots are fork-tender.
Add the green beans and cook for another 2 minutes, uncovered. Add the coconut milk and let simmer for another 5 minutes. Serve warm.