Deductions for ALS (unemployment insurance), the parental leave scheme, and the solidarity pension (Samhaldsfasti) are automatically deducted from your salary, just like tax.
The current rates are:
ALS: 1.25%
Parental leave scheme: 0.71%
Solidarity pension (Samhaldsfasti): 3%
The contribution to the occupational diseases fund (Vinnusjúkagrunnur) is an employer fee and must not be deducted from the employee's salary.