In a large bowl, mix the minced meat, rice, 1/2 cup water and onion. Combine salt, celery salt, garlic powder and pepper. Mix well. Make balls.
Preheat the oven to 175 degrees C. In a large skillet over medium heat, fry the meatballs, drain the fat.
Put in a baking dish, combine the tomato sauce and 1 cup of water. Place the fried meatballs in tomato sauce, turning to coat well.
Cover and bake in a preheated oven for 45 minutes. Open and cook for another 15 minutes.