The prevailing legal documents in the tax field have not yet clearly defined or guided about the time frame during which the tax authority is restricted from conducting inspection and audit at the enterprise. And the Law on Tax Administration regulates the sequence when tax authorities conduct inspections and audit over taxpayers, but provide restrictions on issuing his or her decisions or appraisal in a certain time frame. Therefore, in principle, the competent tax authority may carry out tax inspections and audits over taxpayers at any time as long as reasonable notice is given in advance.
On the other hand, for an act of tax evasion or tax fraud which is not severe enough for penal liability examination, or an act of understating the tax payment or overstating the exemption, deduction, refund, reimbursement, the Law on Tax Administration stipulates the time frame of 05 years as the statute of limitations for sanctioning tax law violations from the date of committing such violating act. This regulation indicates that tax authorities may only sanction administrative violations related to tax law violations committed by the enterprise (including acts of tax evasion or tax fraud which are not serious enough for penal liability examination, or acts of understating the tax payment or overstating the exemption, deduction, refund, reimbursement) if administrative sanctions are imposed within the statute of limitations for those violations (five years from the date of committing such violation). In cases where the statute of limitations for sanctioning has run out, tax authorities will have no competence to apply administrative sanctions on the enterprise that commit acts of violating the tax law. This regulation does not restrict the tax authorities’ right to inspection and control over the enterprise at any stage.
In addition, even if the statute of limitations for imposing a penalty for tax fauld has expired, taxpayers, though are not subject to administrative sanctions as prescribed, shall pay in full tax arrears, evaded taxes, fraudulent taxes, and late payment taxes into the State budget, which will be calculated within 10 years backward of the date of detecting violations. In cases where taxpayers fail to make tax registration, they shall fully pay tax arrears, evaded taxes, fraudulent tax amounts, or late payment taxes for the whole retrospective period counted from the date of detecting violations.
 Article 137.2 of the Law on Tax Administration.
Article 137.3 of the Law on Tax Administration.