The proposed law is designed to achieve what can be translated as "unity of wages" from the original German text. Small unions would still be able to negotiate their own wage agreements, but in case of conflict, the agreement of the biggest union of a particular sector would apply, trumping the various smaller agreements.

The governing coalition stressed that the right to strike would not be touched by the bill, but that it would prevent niche unions from striking for "themselves and not for the greater good," as Labor Minister Andrea Nahles pointed out in parliament Friday.

She was hinting at the recent wave of strikes by train drivers' union GDL and the pilots' union Vereinigung Cockpit, which had severely disrupted rail and air travel in Germany.

On Thursday, the GDL union, which represents 34,000 members, canceled its ninth consecutive strike after agreeing to mediation talks with rail operator Deutsche Bahn. The first round of talks is scheduled for May 27. During the three-week mediation period, the unions are not allowed to go on strike.

The GDL union's core concern is to negotiate its own wage agreements with Deutsche Bahn, which has so far refused to accept two different agreements from GDL and its main rival, the EVG union, which represents 210,000 members, for the same group of workers.

The GDL is now hoping to achieve its aim of a separate agreement during the mediation talks.

Both the opposition and some unions have vowed to challenge the law in Germany's constitutional court. They have accused the government of threatening the survival of the niche unions and "wanting to make striking by small unions impossible," Klaus Ernst from the Left party said in parliament during a debate on the bill.

The head of services union Verdi, one of Germany's biggest, also laid into the government, telling news agency DPA that the law would mean "a slippery slope of political curtailing of union rights."

ng/kms (dpa, AFP, Reuters)