It became PostBank in 1987 and was disestablished and the branches were rebranded when it was acquired by Australia and New Zealand Banking Group (ANZ) in 1989.

The Post Office Savings Bank was set up in 1867 to encourage thrift by ordinary people, and was immediately successful.

[2] Business was conducted from post offices which were located in towns and cities all over New Zealand.

By the 1910s customers were asking for the ability to withdraw their funds by cheque but successive postmasters-general refused to allow this, stating that the Post Office Savings Bank was not the same as a commercial bank, having as its objective thrift and regular deposits, not convenience.

PostBank was formed when the New Zealand Post Office (a former Government Department) was split up by the Postal Services Act 1987 into Post Office Bank Ltd (trading as PostBank), New Zealand Post Ltd (a postal services company) and Telecom Corporation of New Zealand Ltd (a telecommunications company).