One of South Korea's two umbrella labor groups has announced it will wage an “all-out battle” against a low-wage carmaking joint venture agreement between the Gwangju city government and Hyundai Motor.

The Ulsan branch of the Korean Confederation of Trade Unions said Thursday that the five-year wage suspension clause in the deal destroyed the country's labor rights guaranteed by the Constitution.

Calling that part of the agreement illegal, the labor group said it will conduct a legal review of the wage negotiation suspension. The group didn’t take part in the deal negotiating process.

Under the joint venture agreement to establish a car plant in the southwestern city, workers will be paid less in return for increased hiring, with the local government providing workers with housing, education and health care.

The labor group also criticized the deal for threatening production and jobs.

The rival umbrella group Federation of Korean Trade Unions, which participated in the negotiations. welcomed the deal.