Gulnara Shahinian was speaking on March 27 at the end of an official visit to Kazakhstan to assess the initiatives taken by the government since 2012.
The independent expert was designated by the UN Human Rights Council to monitor, report, and advise on slavery.
Shahinian urged the authorities "to urgently put in place enforcement and monitoring mechanisms to fully implement the new laws and policies" toward eliminating slavery in the country.
She welcomed changes to the legislation simplifying the process of issuance of work permits for migrants.
She also said children of migrant workers employed in accordance with migration laws are now allowed to attend school, with the same rights as all other children.
But Shahinian reiterated concerns on children's access to medical care.