I understand that you have hired an agency which does some specialised job in your establishment for short period. The job is not of permanent nature and the agency being specialised for that job, undertakes such job of various clients.
As per CLRA, there is no such distinction for contract of temporary or permanent nature or contracts for short or long period. If there is employment of outside manpower under a contract oor work order, it will attract provisions of CLRA/ PF/ ESIC ect. The basic condition under CLRA is that if the contractor employed 20 or more person, he should take a licence. Licence may be for one year or for shorter period as per requirement of the job. The cases decided by courts may have different facts and circumstances.
I, therefore suggest yoy to ask the agency to take a license under CLRA
CLRA defines contractor to mean someone who produces a given result through the engagement of Contract labour.If those engaged are the permanent employees of the contractor they are are not contract labour.
Permanent employees would be eligible for Bonus,Gratuity,retrenchment compensation as applicable to the contractor as an establishment covered under the definition of industry under the ID Act.Contract labour would not be eligible for any of these benefits.
For instance Bonus would be paid to the regular employees of the contractor based on the profits-allocable surplus- of the employer-contractor,gratuity would be paid based on the total-service rendered by the employees in the employment of the employer-contractor(not limited to only service rendered in one contract) etc.If at the end of the contract the employer should terminate the permanent employees they would be eligible for retrenchment compensation and other compliances under the ID Act would be required to be followed for retrenchment.This would not be the case if he had engaged contract labour-no bonus,no gratuity,no applicability of retrenchment provisions of ID Act.
In short in the former case he is an employer in the nature of an industry covered under ID Act.In the latter case he is a Contractor under CLRA in which case only the CLRA would apply.