The delay was prompted by concerns over businesses’ lack of technical preparedness. Niveus said the extension gives companies additional time to review and improve their data reporting processes to avoid tax risks resulting from errors.

The core of the modification is that 21 types of errors that had previously only triggered warnings will be reclassified as serious errors (“errors”) from September. In such cases, affected invoices will not be accepted into the NAV system, potentially leading to complications with VAT filings and data reconciliation.

“Many people believe that the automatic connection between the invoicing software and NAV guarantees error-free reporting, but this is not the case. From September, the system will go live, which means that incorrect data will not only trigger warnings but may also lead to a failed data submission, possibly resulting in a tax authority procedure,” said Erzsébet Antretter, head of Niveus’ tax advisory division.

NAV will provide a testing window from September 1 to 15, allowing businesses to assess and, if necessary, adjust their systems ahead of full enforcement.

According to Niveus, companies should begin preparing now by reviewing what data is being transmitted from their invoicing software, updating their systems, and ensuring appropriate oversight over automated data reporting.