UPDATE: Transperth have confirmed trains on the Mandurah Line are currently delayed due to a technical issue.
Trains will continue to run, however they will not be running to the regular schedule.
Transperth advised people to allow extra travelling time and be aware that delayed trains may not connect with timetabled bus and train services.
Trains have resumed running between Elizabeth Quay Station and Leederville Station on the Joondalup Line as of 7.19am.
Transperth thanked commuters for their patience and advised they may experience minor delays as services returned to normal.
EARLIER: Northern commuters may face difficulties heading into the city this morning after technical issues forced Transperth to cancel some trains on the Joondalup Line.
Trains on the Joondalup Line are currently cancelled between Elizabeth Quay Station and Leederville Station.
Replacement buses are currently being organised to run between the two stations.
Transperth apologised for the inconvenience and urged people to allow extra travelling time and be aware replacement buses may not connect with timetabled bus and train services.
If you require assistance regarding service disruptions or planning your journey this morning, please call the Transperth InfoLine on 13 62 13 (TIS: 13 14 50).
Hearing or speech impaired commuters can call via NRS 133 677 and ask for 13 62 13.