Western Australia's public transport department has taken its websites and internal systems offline after detecting an attempted hack this morning.
The Public Transport Authority, which runs the state's trains, buses and ferries, shut down the websites for Transperth, RightTrack, School Bus Services, Get on Board and its own PTA website just before midday AWST (3pm AEDT).
Staff are also unable to access internal systems, including email, in an attempt to mitigate against the attack.
A spokesperson said the department had acted out of caution after spotting the security issue and did not believe the attacker's bid at entry had been successful.
They said the department was working to get the sites and systems back online today.
Real-time train tracking on the Transperth app is unavailable as a result.
While the SmartRider system, WA's travel smart card, is still operational, online services like balance checking are not available. SmartRiders can still be topped up at stations, outlets and on buses, the department said.
PTA said passengers could call the Transperth infoformation line on 13 62 13, but warned wait times were expected to be long given likely high call volumes.
Update 29.3.16: The main Transperth website returned to service over the weekend, but the real-time tracking feature as well as the PTA's other websites remain offline.
A spokesperson said the department had focused on getting the Transperth website, which carries the majority of traffic, back up as a priority.
He said progress with other services was limited over the long weekend due to the unavailability of third-party providers.
The department is checking and cleansing the remaining services to ensure nothing had been compromised, and was "reasonably confident" it had caught and prevented the attack early, the spokesperson said.
He did not provide a time of full service restoration.