Hundreds of Egyptian tax collectors have rallied against a new law seeking to reform the country's mammoth civil service, calling it unfair and unconstitutional.

Critics say the law — passed in the absence of a parliament in Egypt — exempts segments of the civil service, including doctors and teachers, and threatens to dramatically reduce the force of more than 6 million employees.

About 2,000 tax and customs workers protested Monday in Cairo, urging President Abdel-Fattah el-Sissi to scrap the law and fire his finance and planning ministers. It was one of the largest anti-government rallies amid a crackdown on dissent.

The law, endorsed before Egypt hosted a conference in March to draw foreign investment, aims to reform a complex wages system and introduces evaluation as basis for promotion.