[25] In my opinion, therefore, the Commissioner complied with the administrative duties imposed by s 60(1). If I am wrong in that conclusion, in my opinion the failure of the Commissioner to discharge those duties would not affect the validity of the warrants. The failure occurred after the valid issue of a warrant. Pursuant to s 47(a), each warrant was activated when notification of the issue was received by or on behalf of the Managing Director of the carrier. There is no suggestion in the Act that a subsequent defect in carrying out the administrative responsibilities imposed by the Act affects the validity of the issue of the warrant or the commencement of the operation of the warrant. In those circumstances, even if the Commissioner failed as suggested, in my opinion the interceptions occurred under valid warrants for the purposes of s 7(2)(b) of the Act. On that basis, the prohibition in s 7(1) does not apply to the interceptions.