Central Organisation of Trade Unions Chairman Peter Odima has put on notice people employing minors.
Speaking in office on Friday, Mr Odima said there has been an increase in the rate of employment of minors as house girls and shop attendants.
"According to the Constitution, children are entitled to education since the national government is offering free and compulsory education," he said.
He said Cotu would conduct a research to establish the total number of minors employed in the country.
"At the moment I have over fifty cases that I am working on where minors were employed and in the long run they were denied payment since they do not have IDs and cannot defend for themselves."
He added that he will be sending his officers to arrest employers employing minors without paying them which is against the constitution.
"I give a stern warning to parents who allow their children to be employed instead of going to school that they will be arrested and charged for child neglect," he said.