Labor unions and the ACLU of Michigan say the state's right-to-work law should be struck down because people were locked out of the Capitol when the bills were initially passed.
An amended lawsuit filed Thursday asks an Ingham County judge to invalidate the law because the Open Meetings Act was violated.
Additional people were blocked from coming into the Capitol for more than four hours on December 6 after state police had safety concerns.
The suit doesn't take issue with the substance of the law that prohibits forcing workers to pay union dues or fees. Opponents for now instead say the law can't stand because it was passed in a place that wasn't open and accessible to the public.