After a Boeing 747 had landed on runway 34L the crew was instructed to taxi via runway 25 and taxiway Yankee (Y). Jeppesen Sydney terminal chart 10-9, dated 18 December 1998, was used to provide taxi guidance to the crew. That chart depicted taxiways G3 and Y leading off to the north of runway 25. However, the chart was ambiguous in that there was another letter "Y" displayed to the south of runway 25. The crew interpreted taxiway G3 to be taxiway Y on the basis of that information. The crew subsequently turned the aircraft onto taxiway G3, which was closed. The aircraft was then stopped until cone markers and unserviceability lights, which marked taxiway G3, had been removed.
The taxiway system in that area of the airport had been undergoing significant changes. A Notice to Airmen (NOTAM) had been issued advising that taxiway G3 was only available during daylight hours. The end of daylight had occurred 29 minutes before the incident.