This includes the organisation's first full-time chief executive, Gavin Slater.
The DTA had 342 staff on its rolls at the end of June 2018.
Sixty percent of the staff were employed in Canberra while the remainder work in Sydney.
The DTA has been in the news recently over Govpass, the single-identity service that is supposed to be tested in October.
But there is no cloud provider for the service, after the unceremonious dumping of Vault, a company that has gained Protected cloud status from the Australian Signals Directorate, which means it can host top secret government data.
Contacted for comment about the staff turnover, a DTA spokesperson said: "The DTA recruits skills and expertise as required to deliver on key priorities. The DTA’s workforce is a mix of APS, contractors and secondees that deliver on the government’s digital transformation agenda.
"DTA’s agile ways of working encourage teams to work across projects that start and finish much quicker than the traditional ones. This allows DTA to bring in skills from across the public and private sector for short periods and focus on delivering outcomes in a quick fashion.
"DTA is proud of the work we have done involving multi-disciplinary teams from across the APS. This allows us to increase the capability of the public sector and also to deliver outcomes in a truly collaborative way."