Customers of Bank of New Zealand and Kiwibank may face delays in getting through to the lenders, with both banks' primary call-centres based in Wellington.

Much of the capital city's CBD is in shutdown as landlords send in structural engineers to assess the damage caused by the 7.5 magnitude earthquake in the upper South Island, which was felt through most of the country last night. The country's major lenders are progressively opening branches once they've passed building inspections, though Kiwibank and BNZ expect their call-centre operations to face delays with much of that work based in the capital city.

BNZ's Harbour Quays office in Wellington has suffered "visible damage" and the lender is working with its landlord and earthquake assessors to determine how bad it is, a spokeswoman said in an emailed statement.

"While this happens, this office will be closed. A large part of our call centre operates from that office, so it's likely there will be a delay in answering calls today - we appreciate our customers' patience in advance," she said.


Similarly, Kiwibank expects delays at its call centre which has been shifted to Hastings from Wellington, while its head office could be closed for two to three days, a spokesman said.

ASB Bank said there hadn't been any disruption to its systems, though some branches in the affected regions were closed as a precautionary measure, while Westpac New Zealand said its branches were being opened once they passed inspection and that mobile and phone banking were available.

ANZ Bank New Zealand said 16 branches, mostly in the Wellington CBD, would remain closed until further notice, while a further 22 had been cleared to open. The lender's Wellington corporate offices were also closed and "many of our technology functions in Wellington have either been diverted to other locations, or staff are working remotely. All online services have been maintained."

The Wellington-based NZX market opened as at 10am to a muted response and the Reserve Bank said its payments system is operating normally out of its New Zealand office.

Payments NZ chief executive Steve Wiggins said all the core payments systems were functioning well, with no issues at Paymark's main switch and that several banks had confirmed it was business as usual. Where there might be issues in the payments system, that was in wireless payments if telecommunications networks have any issues, he said.