KAZ has been supplying basic services to ING for the past three years but the new deal expands the company's responsibilities.
A KAZ spokesperson told ZDNet Australia: "Since 2002 KAZ supplied desktop, e-mail, file and print services [to ING Australia]... the contract has now been extended to provide mid-range system services".
The new contract includes the management of ING's mid-range servers, storage, operating systems, middleware and databases, which run on both Windows and Unix platforms.
Mike Foster, CEO of KAZ said his company has a solid relationship with ING and hopes to build on this over the next five years.
"The signing of the five year contract with ING Australia further strengthens KAZ's position in the financial services sector... KAZ has an excellent working relationship with ING and we see this relationship only strengthening over the next five years," said Foster.