IG Metall said its members would down tools for a few hours a day after the auto giant and union leaders failed to agree on how to cut costs.

Volkswagen has rejected a proposal from labor representatives that they said could avert layoffs and factory closures. VW said it wouldn't have delivered the advertised savings. Strikes loom in the brewing labor dispute.

German automotive giant Volkswagen is facing the prospect of strikes, after the IG Metall union declared the end of a truce in their labour dispute on Saturday, which had prohibited industrial action during initial negotiations.

Volkswagen workers offered on Wednesday to back 1.5 billion euros ($1.6 billion) in cost savings if it rules out closing plants in Germany, but warned the automaker would face an historic battle if it pressed ahead with swingeing cuts.

Workers at Volkswagen could go out on strike across Germany as soon as next week, the IG Metall union said in a notice on Friday, as a clash between labour and management over layoffs and plant closures escalates.

An agreement not to hold strikes ended on November 30. "Accordingly, strikes are possible and also necessary from the beginning of December," the union said. "Volkswagen will determine at the negotiating table how long and how hard the conflict will be - the VW workforce throughout the country is ready to strike," it added.

Volkswagen, under pressure from high costs and Chinese competition, rejected union proposals for cost savings on Friday, just days ahead of planned walkouts meant to avoid unprecedented plant closures.

German Volkswagen employees have reached their limit. They are threatening a warning strike that could potentially escalate into a prolonged protest. On 21 November, after the third round of negotiations with the company's management ended in failure,

Germany's powerful IG Metall union this month proposed 1.5 billion euros ($1.6 billion) in cost savings, including forgoing bonuses for 2025 and 2026. "Sustainable savings of 1.5 billion euros cannot be ascertained even after intensive analysis", the company said on Friday.