Story highlights Investigators said Restaurant Associates violated the McNamara-O'Hara Service Contract Act.

The company Restaurant Associates and a subcontractor shorted 674 employees.

(CNN) The Department of Labor is seeking to bar a company from receiving federal contracts after a probe found that hundreds of US Senate cafeteria workers were wrongfully denied over $1 million in wages.

The DOL said Friday that the company, Restaurant Associates, and a subcontractor would be punished for stiffing 674 employees by classifying them in lower-wage categories, while also requiring them to work before the scheduled start time without proper pay or overtime.

"Workers in the restaurant industry are among the lowest-paid workers in our economy," said the Labor Department's David Weil earlier this year. "Most struggle to afford life's basic expenses and pay their bills; they shouldn't have to deal with paychecks that don't accurately reflect their hard work and the wages to which they are legally entitled."

Investigators said Restaurant Associates violated the McNamara-O'Hara Service Contract Act and the Fair Labor Standards Act. Its subcontractor, Personnel Plus, flouted just the former.

Clarification: Story has been updated to reflect the latest development is the move to ban Restaurant Associates from receiving future federal contracts.