The central bank joined the Federal Housing Finance Agency, the Office of the Comptroller of the Currency, the Office of Thrift Supervision, the Department of Housing and Urban Development and the Special Inspector General for the Trouble Asset Relief Program (TARP) in the biggest expansion of the group since its formation in July 2002.
In a statement, the Justice Department said the new members had been added to aid its crackdown on mortgage and securitization fraud.
Deputy attorney general Mark R Filip, the task force's chairman, said the inter-agency collaboration it creates is "invaluable" in tackling corporate-level mortgage fraud.
"These new members reflect the breadth and depth of the mortgage crisis that we are now confronting, and the urgency of the task before us," he added.
Other members of the task force include seven US attorneys' offices, the director of the FBI and the head of the Securities and Exchange Commission.
Since its inception, the body has helped to secure approximately 1,300 corporate fraud convictions, including indictments against over 200 chief executives and presidents.
A recent poll found that Florida led all US states in cases of mortgage fraud.