A recent report into key threats to New Zealand's critical infrastructure has raised speculation that the country's banks are looking to move their processing operations offshore, to Australia.
All banks except TSB Bank in New Zealand, are majority owned by overseas financial institutions.
Many, such as the ANZ, WestpacTrust (Westpac Banking Corporation), ASB Bank (75 per cent owned by the Commonwealth Bank of Australia) and the Bank of New Zealand (National Australian Banking Group), are either owned outright or majority owned by Australian banks.
The report released by the E-Government Unit of NZ's State Services Commission, 'Protecting New Zealand's Infrastructure from Cyber-Threats', highlights its concern of the "desire of some New Zealand banks to move their retail processing offshore".
According to the report at least one had already done this and others were considering the move.
ANZ has confirmed it moved its core processing from NZ to Australia nearly two years ago.
A central data centre, in Melbourne, houses the mainframe processing and data storage, which handles all customer information. Branches in NZ continue to undertake retail processing.
Rita Zonius, media relations manager with ANZ, said the decision to centralise the system was made in order to standardise its platform.
"Eftpos NZ (which is owned by ANZ) and ATM processors still sit in New Zealand in data centres in Wellington and Auckland. Telephone banking in NZ also sits domestically, as well as several back office systems such as mortgage operations."
David Lording, head of media relations and issues management for Westpac Banking Corporation, denies the group was centralising operations.
"You could discount us, we are not moving WestpacTrust's processing offshore."
Surprisingly, the report also said the Reserve Bank of New Zealand (RBNZ) was planning to move the computers for its "real time gross settlement" to Australia. This system manages the relative position of all New Zealand banks and is core to the banking system.
The New Zealand government does not own or directly control much of the critical infrastructure within New Zealand.
"The RBNZ is moving to interdependency with international banking, a move that the rest of the New Zealand banking sector also appears to be adopting," the report said.
The computers for the "Austraclear system", currently operated by the Reserve Bank, are also being moved to Sydney. Austraclear is the main means of settling debt securities transactions in New Zealand and is crucial to the New Zealand financial markets.
"There are two main risks in the movement of banking systems offshore. Firstly, adverse events in Australia, such as industrial action."
The second problem the report outlined was that of telecommunications failure. "This threat has to be seen as one of low likelihood but high impact."
The report said the move offshore by banks would increase New Zealand's reliance on "extended telecommunications paths" and "perhaps raise issues of sovereignty".