Rhoda Holmes, TCNZA general manager Commonwealth Bank, said the Multiprotocol Label Switching (MPLS) network will support CBA's more than 1100 branches and administration sites across Australia.
"The enhanced network will also provide a platform for the applications and customer programmes that are integral to the bank's CommSee project," she said.
CommSee -- part of CBA's Which New Bank initiative -- is a programme of work that will enable the bank to have a single view of customer data.
Under the new agreement, TCNZA will design, install and operate the MPLS network. TCNZA will also be responsible for the new network's ongoing management and development.
Holmes said work has already started on the agreement and that they are expecting a "swift and smooth rollout of the new network over the coming year."