Workers at Volkswagen have briefly halted production at three German plants in protest at the firm's cost-cutting plans.

With talks continuing between VW and its main unions, staff temporarily went out on strike at VW sites in Brunswick, Hanover and Kassel on Friday morning, the BBC reported, adding that key union IG Metall warned that more so called warning strikes would continue alongside the negotiations.

VW, which on Thursday reported a 44% drop in profits, wants a pay freeze and the carmaker's chief representative at the talks with the unions, Josef-Fidelis Senn, told the BBC the company was "negotiating hard" for a two-year wage freeze for the roughly 100,000 workers at its six western Germany plants.

VW has said it wants to achieve a 30% reduction in labour costs by 2011, and has warned that 30,000 jobs may be at risk.

Senn reportedly accused IG Metall of dragging its feet on Thursday night. "One has the impression that IG Metall is moving at a speed that unfortunately doesn't fit in with reality," he told the BBC.

IG Metall's lead negotiator Hartmut Meine reportedly said that while the union was still confident that it could secure job guarantees, VW was not backing down from any of its cost-cutting proposals.

Senn said VW's plan to couple pay with the company's earnings performance would compensate workers for the wage freeze.