Opel workers fire warning shot over bonuses: sources

FRANKFURT (Reuters) - The 25,000 German workers at Opel rescinded an agreement to forego their holiday bonuses and now demand the carmaker pay the balance of around 70 million euros ($100.1 million) in cash due next week, several sources said on Monday.

"This is the first warning shot," one person familiar with the matter told Reuters.

Although the demand would hurt Opel -- leading in a painful drain in precious liquidity -- German labor leaders hope the move will put pressure on the board of General Motors to finally approve a majority sale of Opel to Canadian auto parts supplier Magna.

Opel is currently surviving on a 1.5 billion euro bridge loan from the German government.

This is the "mildest" form of protest the union organized workforce in Germany could take, the person explained, adding that the 25,000 workers could ultimately decide to demand the 4.2 percent industry wage hike from last year's collective bargaining agreement that they intended to waive for five years.

"This would then represent an amount due equivalent to the equity contribution of either the two bidders, RHJ or Magna," the source explained, referring to the two competing bids of 275 million euros and 500 million euros, respectively.

Another person said that while only Ruesselsheim and Bochum works councils agreed to demand the holiday bonuses back, colleagues at the Kaiserslautern and Eisenach plants would follow with similar demands -- possibly as early as Tuesday.

(Reporting by Christiaan Hetzner)