Metlink earlier said all trains in and out of Wellington railway station were suspended “until further notice”.
A KiwiRail spokesman said staff were “working to fix the fault as quickly as possible”.
The fault meant trains were “unable” to move in or out of Wellington Station.
Stranded commuters have voiced their frustration online.
One affected passenger posting on social media said they had been “strongly encouraged” to work from home if possible.
Another wrote: “Where’s the 7.04 train to Wellington from Naenae? Just no service, no bus replacement, no communication as per usual.”
“Just another day on our trains,” another said.
- More to come
Sign up to The Daily H, a free newsletter curated by our editors and delivered straight to your inbox every weekday.