Transferring a Posted Worker to a New Site in Denmark 2026
Moving a posted worker to a new construction site in Denmark sounds like a simple administrative task, but it triggers a chain of obligations that can catch even experienced staffing agencies off guard. The A1 certificate issued by ZUS, which proves that the worker continues to pay social contributions in Poland, is tied to specific posting details, including the place of work. The RUT register maintained by the Danish Building and Construction Authority carries the same sensitivity. Change the site, and both documents potentially need to be revisited before the worker sets foot on the new address. Getting this wrong exposes the agency, the Danish client, and the worker to scrutiny from Arbejdstilsynet, SKAT, and Polish inspection bodies including PIP.
Step 1: Check Whether the Transfer Triggers a New Obligation
Not every internal reassignment automatically invalidates an existing A1 certificate or RUT entry. The key question is whether the change is material. Under EU Regulation 883/2004, which governs the coordination of social security systems across member states, an A1 certificate covers a specific posting period and, in practice, a specific assignment. If the new site is for a different Danish client, involves a substantially different scope of work, or falls outside the geographic area described in the original posting documentation, the existing A1 is almost certainly no longer sufficient on its own.
Similarly, the RUT system requires that the registered information accurately reflects the actual work being performed in Denmark. A change of work address is one of the details that must be kept current. Danish authorities take RUT accuracy seriously, and discrepancies between registered data and reality are a common trigger for inspections. For a broader look at how SKAT cross-references these records, see our guide on How SKAT Audits Staffing Agencies: Key Mistakes and Penalties 2026.
Step 2: Gather the Required Documents Before You Do Anything Else
Before submitting any update, assemble the complete documentation package. You will need the worker's existing A1 certificate, the original posting agreement drawn up under the Polish Kodeks Pracy provisions implementing Directive 96/71/EC, the new work order or contract addendum specifying the new site address and expected duration, and the Danish client's CVR number. If the worker has already been in Denmark for a significant period, check the 183-day threshold carefully. Our dedicated article on Construction Worker Rotation Every 183 Days: A1 Status Guide 2026 explains how the calendar is calculated and what happens when the limit approaches.
On the Polish side, ZUS will want evidence that the employer genuinely operates in Poland and that the posting remains temporary. Gather recent payroll records, proof of the employment contract, and any prior ZUS correspondence relating to the worker's posting. Missing even one of these documents can delay the process by weeks.
Step 3: Update the RUT Registration
The RUT register is managed online through the portal operated by the Danish Business Authority. Employers or their representatives log in and amend the existing service notification to reflect the new work address and, if applicable, a revised end date. This must be done before the worker starts at the new site, not after. Danish law under LOV 89, the act governing the registration of foreign service providers, does not provide a grace period for retroactive corrections in cases where inspectors discover a discrepancy on site.
If the agency uses a Danish representative or a professional payroll intermediary to handle RUT filings, notify them immediately when a transfer is confirmed. Delays in internal communication between the Polish agency and its Danish partner are one of the most common reasons workers are found at unregistered addresses during Arbejdstilsynet spot checks.
Step 4: Apply for a New or Amended A1 Certificate Through ZUS
In Poland, A1 certificates are applied for through the ZUS e-Platforma portal at zus.pl. The relevant form for posting is the US-54 application for a certificate of applicable legislation. When a material change occurs mid-posting, the standard practice is to apply for a new certificate reflecting the updated assignment details rather than attempting to annotate an existing one.
Processing times at ZUS vary. For straightforward cases where the employer has a clean compliance history, decisions can come within a few weeks, but complex cases or those involving workers who have been posted repeatedly can take longer. Do not assume that a pending application is sufficient protection if Arbejdstilsynet visits the site. The worker should ideally carry the new certificate, or at minimum written confirmation from ZUS that the application is in progress.
Step 5: Confirm Receipt and Keep Records
Once ZUS issues the updated A1 and the RUT entry reflects the new site, retain copies of everything in a format that can be produced quickly during an inspection. Danish authorities are entitled to request documentation on site, and the worker, the agency, and the Danish client can all be held responsible for gaps. Store records for at least the duration of the posting plus a reasonable buffer period, as both Polish and Danish audit windows extend beyond the end of a contract.
The Polish Labour Inspectorate, known as PIP, also has authority to review posting documentation when workers return to Poland or when complaints are filed. Keeping tidy records is not bureaucratic caution, it is the only reliable defence if a dispute arises months after the posting ends. More information on Polish employer obligations is available at pip.gov.pl.
Common Mistakes to Avoid
The most frequent error agencies make is treating a site transfer as a purely logistical matter and neglecting the paperwork until after the worker has already moved. A hypothetical example illustrates the risk well: imagine an agency relocating a carpenter from one Copenhagen suburb to another at short notice because a client project was delayed. The RUT still shows the original address, the A1 refers to the original project description, and an Arbejdstilsynet inspector visits the new site within days. The result is a formal notification of non-compliance, potential fines, and a disrupted relationship with the Danish client, all of which could have been avoided with a single afternoon of administrative work done in advance.
Another common mistake is underestimating how quickly the 183-day social security threshold accumulates across multiple postings. Days spent in Denmark on previous assignments count toward the total even if they were under different contracts. Track cumulative days carefully and plan rotations accordingly.
Finally, agencies that are scaling up their operations in Denmark should consider how digital tools are changing the compliance landscape. Platforms that automate RUT updates and flag expiring A1 certificates are increasingly common, and our overview of How AI Is Changing Recruitment in Agencies Sending Polish Workers to Denmark 2026 covers how technology is reshaping administrative workflows for cross-border staffing.
Actionable Advice for Agencies and Construction Managers
When a transfer is confirmed, treat the RUT update and the ZUS application as day-one tasks, not afterthoughts. Assign a named person in your organisation who owns the compliance checklist for every active posting. Verify the Danish client's CVR number before filing. Keep a copy of the A1 certificate accessible to the worker at all times, whether digitally or in print. And if you are unsure whether a given change is material enough to require a new A1, contact ZUS directly or consult a specialist in cross-border employment law, the cost of professional advice is always lower than the cost of a compliance failure discovered during an inspection.