It is illegal for employers to withhold employee’s passports. As Marry Catherine said, it is the property of your government. I had a situation where the passport of one of my in-laws was withheld by the employer in the UAE. I did address the issue with the labor ministry. The lady said it was normal practice for employers to withhold the passport. I proposed to her that I contact the embassy and declared the passport illegally withheld to the police. She went silent and made a phone call. The employer showed up with the passport within 30 minutes. Everyone in government knows that the practice is illegal.