Over 30,000 workers downed tools on Wednesday morning, including over 8,000 staff at factories of German car maker Opel, IG Metall said in a statement.

"It's a strong signal for pay talks and for PSA in France," IG Metall chief Joerg Hofmann said of the strike at Opel's main site in Ruesselsheim.

Peugeot brand owner Groupe PSA acquired Opel-Vauxhall last year and has been pursuing a restructuring plan to return it to profitability.

Wednesday's strikes mean around 468,000 industrial workers have taken part in action since last week, the union said, with further walkouts planned for Wednesday afternoon and evening.

IG Metall, Germany's biggest trade union, on Tuesday said it would decide on Jan. 26, after the current round of wage talks, whether to escalate the dispute into 24-hour strikes.

(Reporting by Victoria Bryan; Editing by Jon Boyle)