Criminal Code Warning: this is not an official translation. Under all circumstances the original text in Dutch language of the Criminal Code (Wetboek van Strafrecht) prevails

Section 77t 
1.  The court of first instance that tried the serious offence for which the measure has been imposed 
may, on application of the Public Prosecution Service, extend the term, referred to in section 77s(6, 
first sentence), for a maximum of two years each time. The Public Prosecution Service may submit 
an application for extension of the measure no earlier than two months and no later than one 
month before the date on which the measure is conditionally terminated. Sections 509oa and 509q 
of the Code of Criminal Procedure shall apply mutatis mutandis.