tax implication on job worker

I Want to Know what will be tax implication on that labour,that is whether he/she has to pay service tax or excise duty Eg: Principal is providing raw material to job worker,and after the process done by that job worker whice amounts to manufactuer. after the such process job worker returns that finished goods to principal and recive payament as labour charges. my question is what will be tax implication on that job worker.