The suit would be filed on behalf of the Republican-controlled House.
Speaker John Boehner provided no details of the claims to be made in the suit. He had privately briefed members of his rank and file on his plans yesterday.
Republicans have long accused Obama of selectively enforcing the health care law that bears his name, and doing the same with immigration legislation long on the books.
At his weekly news conference, Boehner said the US Constitution makes it clear the president's job is to faithfully execute the law.