Preheat oven to 240°C. Tie the beef at regular intervals with unwaxed white kitchen string to secure. Reserve 3 whole sprigs of rosemary. Coarsely chop 1 tablespoon of the remaining rosemary. Combine the chopped rosemary, oil and garlic in a small bowl. Rub the rosemary mixture over the beef. Thread the reserved rosemary sprigs under the string on the beef. Season with salt and pepper.
Heat the extra oil in a roasting pan over high heat. Add the beef and cook, turning occasionally, for 6 minutes or until brown all over. Roast in oven, basting regularly with pan juices, for 15-20 minutes for medium-rare or until cooked to your liking.