Requesting a NEN 4400 certificate from a labour provider or subcontractor
As a client, you request a NEN 4400 certificate from your labour provider or subcontractor to show that the supplier has been inspected. In practice, this means a declaration of registration from the Stichting Normering Arbeid (SNA, the Dutch Foundation for Labour Standards), combined with a check in the register. A loose PDF is not enough. According to the SNA FAQ , the declaration only shows the download date, so you must check the registration yourself.
This page explains what you request and what you put in the contract. For the check itself, read checking the SNA register. For what the declaration means, read the NEN 4400 declaration.
Last checked: 28 October 2026.
Which documents do you request?
| Document | Why | How to check |
|---|---|---|
| SNA declaration of registration | Confirms the registration at a point in time | Compare name and Chamber of Commerce number with the contract |
| Current registration in the register | Shows the current status | Search by Chamber of Commerce number on normeringarbeid.nl |
| Chamber of Commerce extract (KvK-uittreksel) | Confirms the legal entity | Check that the name matches the declaration |
| Inspected activity | Confirms what is certified | Matches your assignment |
| Certificate from the inspection body (optional) | Extra evidence, for example from Kiwa | Compare with the register, which remains leading |
When applying, SNA requires a Chamber of Commerce extract that is no more than three months old. For your own check, you decide how old the extract may be. Three months is a logical choice, but it is not a rule for clients.
A fictional contract
Construction company Halm hires staff through labour provider Delta. The contract includes the following clause, as an example:
On request, the labour provider supplies a Chamber of Commerce extract that is no more than three months old and confirms the registered activity. The client may check the registration in the SNA register and download a declaration itself.
Halm checks the registration each time it hires new staff and keeps the declaration it downloaded itself, with the date. This example is fictional and is not a legal model. Have a lawyer review your contract.
A declaration that the labour provider supplies itself is not the same as a check in the register. The download date on the PDF may be old. Download a new declaration yourself.
Step-by-step when requesting
- Request the declaration and note the date you received it.
- Check the Chamber of Commerce number and the legal name in the register.
- Compare the activity with your assignment. See applying for the SNA certificate for the activities.
- If there is a chain of subcontractors, also request the declarations from those subcontractors.
- Record the check in your purchasing or hiring records.
Common mistakes
- Only asking for the document. A declaration without a register check says nothing about the current status.
- Wrong entity. A parent company has a different registration from the subsidiary you hire from.
- Forgetting the activity. A registration for a different activity is not evidence for your assignment.
- No repeat check. The status can change. Check again with each new assignment.
Frequently asked questions
Is a declaration from a subcontractor enough?
If the subcontractor deploys staff, the declaration from that subcontractor is relevant. Check each party, not only the main contractor.
What if the labour provider has no declaration?
Then the labour provider is not listed as certified in the register. The SNA certificate is voluntary, so this does not mean the labour provider is not allowed to hire out staff. See Wtta and SNA for how the two routes relate.
What do you do if the declaration is old?
SNA does not set a fixed validity period for a registration. An old declaration has therefore not expired, but it is out of date. Search for the supplier in the register again and download a new declaration. If the company is no longer listed as certified, it has been suspended or removed.
Record which declaration you had, when you checked again and what you did next. This lets you explain later why you did or did not continue.
What do you include in a purchase form?
A good purchase form for temporary staff or subcontractors contains the following fields:
| Field | Example | Why |
|---|---|---|
| Legal name | Staffing agency Delta B.V. | Must match the Chamber of Commerce extract |
| Chamber of Commerce number | The number from the extract | Unique identification |
| Registration in the register | Yes, with check date | Evidence of current status |
| Activity | Making labour available | Matches the assignment |
| Declaration date | Download date from the register | Shows when you checked |
| Checked by | Name of the employee | Responsibility |
The form is a tool. It does not replace the check in the register.
How do you keep the file?
Keep a file per supplier with the declaration, the register overview, the Chamber of Commerce extract and the notes from the check. Repeat the check with each new assignment or each extension. A file you can still show two years later is much stronger than a folder full of expired documents.
Also keep the correspondence about deviations. A client who asks questions later wants to see that you paid attention from the start.
What if you do not receive a declaration?
Then ask the supplier what the reason is. The company may be on the list of ongoing applications. According to SNA, it can stay on that list for three months at most. An application is not yet a certificate. In that case, do not accept a declaration that says an inspection is planned as evidence of current registration.
Record the agreement with an end date. Check that date again. If the evidence does not arrive in time, stop the hiring or the contract, unless your contract arranges something else.