"As we have urged repeatedly, we should engage in bargaining over all issues around-the-clock to get Online Cigarettes Store USA an agreement," Scott Sandefur, GM vice president of North American labor relations, wrote in the letter sent to the UAW.
"Your members and our employees lives are being disrupted and they deserve our commitment to getting any remaining issues resolved as quickly as possible," Sandefur added. "We object to having bargining placed on hold pending a resolution of these five areas."
UAW Vice President Terry Dittes, who heads the union's GM department, said in a letter earlier on Thursday evening to GM that the union would not reply to GM's latest proposal until committees discussing five specific issues had completed their work.
Those committees are discussing issues including the fate of four U.S. factories that GM has indicated could Newport Pleasure close, cutting 15,000 jobs in North America, and future technological changes to production.
Dittes said he did not know when the five issues would be resolved, suggesting a final deal may not be close.
UAW workers are concerned that as GM shifts to more electric vehicles it will require fewer workers, and battery production Newport 100s Box may result in workers getting paid less than at existing transmission plants.