Talks for a new four-year labour contract between General Motors Co. and its striking workers cooled Sunday after the United Auto Workers (UAW) rejected the largest U.S. automaker's latest offer.

GM made an offer to the union that basically repeated one that the UAW had previously rejected, said Terry Dittes, the UAW vice-president in charge of the GM department, in a letter to members. The union provided a copy of the letter to Reuters.

"These negotiations have taken a turn for the worse," he said.

"We, in this union, could not be more disappointed with General Motors," Dittes said. "The company has shown an unwillingness to fairly compensate … the UAW."

In a statement, GM said it continues to negotiate in good faith "with very good proposals that benefit employees today and builds a stronger future for all of us."

The company said it is committed to talking around the clock to resolve the dispute.

Impasse linked to new products

Dittes said the UAW made an offer to GM on Saturday that covered wages, signing bonuses, job security, profit-sharing and other issues. GM responded on Sunday morning with its counteroffer, he said, which "did nothing to advance a whole host of issues."

Dittes also sent a sharp letter to GM's vice-president for labour relations Sunday, saying: "You didn't even have a professional courtesy to explain why you could not accept, or why you rejected, our package proposal for each item we addressed."

A person briefed on the talks said Sunday that the union voiced concerns about GM increasing production in Mexico, where it now builds pickup trucks, small cars and two SUVs. The person, who spoke on condition of anonymity because the talks are private, said both sides are far apart on guarantees of new products in U.S. factories.

GM officials previously said the Detroit company's labour rates are the highest in the industry and it needs the ability to build some vehicles in other markets to keep costs down.

The sides have been meeting daily since the GM strike began on Sept. 16.

Canadian layoffs, solutions promised

The strike means about 2,000 workers have been on temporary layoff since Sept. 20 at GM's assembly plant in Oshawa, Ont. They were on a line that makes Chevrolet Impalas and Cadillacs. Nearly 700 workers were handed temporary layoff notices the same day at the GM propulsion plant in St. Catharines, Ont.

Just before the strike began, GM revealed that its offer to the UAW included plans to invest more than $7 billion US in its U.S. plants over the life of the deal.

GM also said it had "solutions" for the Lordstown, Ohio, and Detroit assembly plants that it had previously said would cease making vehicles. Sources said at the time that those plans included a battery plant in Ohio and building an electric truck in Detroit.

Analysts estimate the strike has cost GM more than $1 billion US, while LMC Automotive estimated on Thursday that GM has lost production of 118,000 vehicles through Oct. 2.

Industry analysts say GM is losing more than $80 million US a day as the strike continues. Workers earn $250 per week in strike pay while they're on the picket lines, about one-fifth of what they normally make.

Wages and pensions are among the issues that remained unsettled.

Striking workers have said they want a bigger share of the more than $30 billion US in profits that GM has made during the past five years. But the company wants to cut its labour costs so they are closer to those at U.S. factories run by foreign automakers, mainly in the south.