Kiwibank is moving to some of the shortest opening hours among Whanganui banks.
From January 24 onwards, its Victoria Ave branch will be open to the walk-in public from 10am to 2pm on weekdays.
Staff will be in the office for longer than that, but outside those hours they will only be available by appointment.
When the doors were shut, staff would handle banking matters over the phone, online or undertaking in-person or virtual specialist appointments, spokeswoman Kara Tait said.
The change would free up staff from Kiwibank's "customer touchpoints" to help its customers, she said.