HM Revenue and Customs (HMRC) has formally signed an agreement to lease Erskine House in Belfast for 25 years. The new site will accommodate 1,600 full-time employees from across the department by 2021.
The departments include fraud investigation, business compliance, debt management and tax credits.
Jon Thompson, HMRC chief executive, said: "Our Belfast regional centre is another step in HMRC's transformation into a modern, digitally-advanced tax authority.
"We will bring teams together, promoting closer working relationships, increasing our effectiveness in collecting taxes and targeting the minority who don't pay.
"This is the start of a process that will see staff come together in state-of-the-art facilities, and make HMRC an important contributor to the economy and to communities in Belfast."