Ensure the duck is thawed. Run cold water through the inside of the duck then pat dry inside and out with paper towels.
To make the stuffing, finely grate the rind of the oranges. Remove the pith and dice the flesh. Place the rind and flesh in a bowl with the stuffing mix, seasonings and enough orange to juice to bind. Loosely fill the duck neck and main cavity with the stuffing. Secure the legs and neck with skewers to hold in the stuffing.
Bring the stock to the boil in a pan just large enough to hold the duck. Add the duck, cover, bring back to the boil and simmer for 1 hour, basting occasionally with the stock.
Preheat the oven to 200°C. Place the duck in a roasting pan. Roast for 30-45 minutes until the skin is crisp and the flesh tender. Baste with a ½ cup of the stock twice during roasting.
Meanwhile, discard any fat from the top of the stock to make a sauce. Thicken with a little cornflour, if preferred.
To serve, carve the meat onto a serving platter, remove the stuffing and place it attractively beside the duck.