The RNLI is facing three lawsuits, with a further two threatened, from volunteers claiming unfair dismissal.
Spokeswoman Anna Wardley said: "Obviously we are concerned as we could not function without volunteers - we have about 4,600 working for us. We believe that the law needs to make a distinction between paid employees and volunteers."
Although she could not divulge details of the lawsuits, Wardley added: "Sometimes you get someone who has a personality clash with other crew members. When that happens, someone has to leave, and in rare cases, that person does not just leave quietly."
The Scout Association is being taken to a tribunal at the end of February, again by a volunteer. Head of media Simon Carter said: "As a volunteer-run body, it would be difficult for us to treat everyone as an employee."
In all six cases, the outcome hinges on whether the individuals are classed as employees. Although there is no precedent of a volunteer proving employee status, there have been cases where volunteers have won worker status.
Worker status falls short of the full rights and protections employment brings, but means that the individual is entitled to the minimum wage.