The national demonstration planned for 15 December has been postponed by a day, a spokesman for the socialist trade union federation ABVV said on Wednesday.
The Christian trade federation ACV and the liberal umbrella ACLVB will also participate in the demonstration, they announced earlier.
Organising the action on 15 December proved difficult as there are several events taking place in the capital on that day, including a European summit.
Although the summit lasts three days, including 16 December, this is less problematic, for example, for the number of police officers that can be deployed on the ground, the spokesman explained.
A meeting with the unions took place on Wednesday at the office of Brussels Mayor Philippe Close to find a solution. However, his office declined to comment.
The decision to take to the streets again was made on Tuesday, just a few days after the federal government knocked off a reconciliation proposal to smooth wage negotiations between unions and employers.