The woman was reportedly late getting into a south-bound train at Glen Innes at about 6.30pm yesterday and was trying to open the closed doors when she slipped and fell into the crack.
"She was trying to open the doors but they had already closed and the security guard tried to pull her back but she lost balance," witness Saskia Clegg told the New Zealand Herald.
"She fell in between the ledge and the train and got caught. I was really scared she was actually going to fall onto the tracks and under the train, but that didn't happen."
The woman suffered a severe laceration to a leg.
Witnesses called 111 and the woman was rushed to Auckland City Hospital.
A spokeswoman for the Auckland District Health Board said the injured woman was in a stable condition but could not give any further details.
