Germany’s power trade union Ver.di called for warning strikes at the major ports ahead of a fourth round of negotiations between the unions and the port operators.

Before the next round of negotiations get under way on July 11 and 12, union Ver.di has called for warning strikes across terminals.

Workers at the Port of Hamburg stopped work early on Tuesday, with their colleagues at Bremerhaven taking the same action several hours later.

The union has called on workers in Hamburg to stage all-day walkouts on Tuesday and Wednesday ahead of a fourth round of negotiations.

Negotiations for a new collective agreement for the 11,500 employees of the German North Sea ports began in May.

Many dockworkers in Bremerhaven have been on a strike since early Tuesday.

Employees at the commercial ports of Bremerhaven joined the strike on Tuesday afternoon, with its walkout scheduled to continue till the first shift on Wednesday, Ver.di said on Wednesday morning.

The trade union also called the workers for warning strikes in Emden, Bremen and Wilhelmshaven.

“In the third round of negotiations, we were still far apart,” said Ver.di negotiator Maren Ulbrich. “The offer presented by the employers is not acceptable to us as it is. The expansion of the warning strikes in Hamburg will now once again send a very clear signal to the employers that the employees are serious about their demands.”

Collective agreement negotiations between terminals and unions in Germany have been ongoing for a number of weeks, resulting in strike action from union members at Bremerhaven and Hamburg ports.

Two years ago, the talks were accompanied by a series of warning strikes that closed the ports for around 80 hours.

“Affected Maersk vessels at Hamburg and Bremerhaven will observe the duration of the strike and recover the impact when service resumes fully. We apologise for any inconvenience this may cause, but rest assured our teams are evaluating the situation frequently and making decisions in the interest of minimising any impact on your supply chain,” the carrier Maersk wrote in its customer advisory.

Ver.di warns that it remains to be seen whether there will be another warning strike before the upcoming fourth round of negotiations.