The contract will see Accenture use Oracle's PeopleSoft software to overhaul and modernise the DoD's military pay system.
Accenture will work on the code design, development and testing to support for the new system.
The DoD said it is currently expected that the new system will be operation before the end of 2017.
"Over recent years, Defence has made a significant investment to modernise its ageing military pay system," a spokesperson for the DoD told Defence Connect.
"Accenture has been contracted to design and build the new military payroll using Oracle’s PeopleSoft software, as used for Defence’s public service employees. Within Defence this human resource system is known as the Personnel Management Key Solution (PMKeyS).
"Accenture continues to assist Defence as we approach the finalisation of the new system. The $8.4 million contract enables Defence to modify the new system to meet important policy and legislative changes, including the changes associated with Australian Defence Force Super.
"The work associated with the new contract with Accenture relates to the code design, development, and testing support, to incorporate these final legislative changes prior to the new system’s implementation."