A recent case has seen the Employment Relations Authority award an employee $16,320 in lost wages and $25,000 for hurt and humiliation. 
The employee resigned following the employer’s failure to properly deal with and investigate allegations of bullying and harassment that the Authority ruled had resulted in psychological damage to the employee. Although the employee resigned she had in effect been constructively dismissed.

Employers have a duty to keep their employees safe from both physical and emotional harm.  If you do not deal correctly with bullying or harassment you could be liable for the damage.  If you receive a complaint about this sort of behavior investigate it quickly and deal with the cause.  A failure to do so can be very expensive and disruptive to your business.