The term contract labor is a relative term. For the principal employer (for whom he works), he is a contract employee. However, for the contractor with whom the principal employer has contracted, the employee engaged by him at the workplace of the principal employer is his payroll employee. The relationship that exists is between the contractor and the employee, as that of employer and employee. Therefore, the employee is eligible for all benefits, including bonus and gratuity, as if he were an employee under the rolls of the contractor.
It is expected that the principal employer ensures that the contractor's employee working in his plant receives the bonus as per the Bonus Act. If the contractor has not paid it, the principal employer can intervene, make the payment, and recover it from the payments due to the contractor.
Regards, Madhu.T.K