"Migrants are subject to numerous violations of their rights on the part of employers every day. One of the most frequent violations we have discovered is that migrants are forced to work without a labor contract," said Maria Lisitsyna, a researcher at Human Rights Watch's Europe and Central Asia Division.
She said a labor contract was a necessary requirement for any migrant worker to maintain his or her status in Russia.
"If there is no contract, a migrant ... is considered unemployed and must leave the country within 90 days," Lisitsyna said.
Human rights activists said the confiscation of passports, wage payment delays and the lack of adequate living and safety conditions were next on the list of the most frequent violations of migrant workers' rights in Russia.
Human Rights Watch said most labor migrants in Russia had "almost no idea of their rights."
Russia trails only the United States on migrant worker numbers, Lisitsyna said. According to various sources, there are between 4 and 9 million migrant workers in Russia. Some 80% are from former Soviet republics and are eligible for visa-free entry to Russia. Around 40% of the migrant workers are employed in the poorly regulated construction industry.