After landing at Newcastle-Williamtown Airport, and while taxying to the terminal, the co-pilot of the Beechcraft 1900D aircraft turned the landing lights off. He then contacted Air Traffic Control. During this radio transmission, the MASTER WARNING and right AC bus (R AC BUS) warning captions illuminated, closely followed by illumination of the right fuel low pressure (R FUEL PRESS LOW) warning. The crew immediately carried out the company check list actions for the right AC bus failure, but decided not to implement the actions for the right fuel low pressure warning as the aircraft was close to the terminal. The checklist actions for the right low fuel pressure indication required the standby boost pump to be switched on. The co-pilot then detected an acrid smell in the cockpit and alerted the pilot to flames he had observed coming from the underside of the right engine nacelle. The pilot in command immediately brought the aircraft to a stop, shutting down both engines. Although there was no engine fire warning indication, the crew operated both engine fire handles, making several unsuccessful attempts to discharge the right engine fire bottle. The co-pilot then evacuated the passengers through the forward cabin door, directing them to the flood lit terminal apron area. The pilot in command alerted the RAAF fire personnel by radio of the fire, before turning off the aircraft power and vacating the aircraft. Two of the operator’s maintenance engineers, awaiting the aircraft’s arrival, had noticed the flames emanating from the wheel well area as the aircraft approached. They had immediately picked up two dry chemical powder fire extinguishers and approached the aircraft. Following the feathering of the right propeller, they discharged the contents of both fire extinguishers into the right main landing gear wheel well area, extinguishing the fire. The military fire tender arrived soon after to assist. SIGNIFICANT FACTORS: 1. The right wing landing light wiring cable tie stand-offs were not installed. 2. The right wing landing light wiring was in contact with the surface of one or more fuel lines in the right wing equipment bay. 3. The wiring had electrically arced on the surface of one or both of the fuel lines resulting in holes being made in the fuel line walls with resultant fuel leaks from each line. 4. The fuel had ignited resulting in fire damage to the adjacent aircraft structure. 5. The fuel leaks were unable to be stopped by the flightcrew.