In a bowl, combine the egg, rice, onion, parsley, salt and pepper. Crumble the mince over mixture and mix well. Shape into 3cm approx. balls. Place on the rack in a pressure cooker. Combine the soup, water and Worcestershire sauce; pour over meatballs.
Close cover securely; place pressure regulator on vent pipe. Bring cooker to full pressure over high heat. Reduce heat to medium; cook for 10 minutes. (Pressure regulator should maintain a slow steady rocking motion or release of steam; adjust heat if needed.) Remove from the heat. Immediately cool according to manufacturer's directions until pressure is completely reduced.