Answer: Yes, they can.
Even if the Federal Tax Authority (FTA) has issued an enforcement instrument for tax collection (e.g., based on a decision by the FTA Director), the taxpayer has the right to challenge it through a substantive enforcement dispute if they claim that the amount is not actually due (for example, due to erroneous registration or miscalculation).
This is supported by Article 239 of Federal Decree-Law No. 42 of 2022 on the Promulgation of the Civil Procedure Code, which allows the initiation of a substantive enforcement dispute even after the commencement of enforcement proceedings.
Additionally, under Article 40 of Federal Decree-Law No. 28 of 2022 on Tax Procedures, a decision by the FTA Director to collect a tax constitutes an enforceable instrument, but it does not have the same legal status as a court judgment.
Relevant case law:
Case No. 1322 of 2024 / Federal Supreme Court / Administrative