The lawsuit filed in federal court by Agassiz Energy LLC says Wanzek Construction and three other companies misrepresented themselves as a corporation with experience in designing and building ethanol plants.
Wanzek Construction officials were not immediately available for comment.
The lawsuit seeks damages of nearly $830,000.
Plans to build the plant near Erskine, Minn., were suspended last year. Agassiz Energy officials blamed the delay on the high cost of corn and lower prices for ethanol.