9. Section 22 of the Principal Act is amended by adding at the end the following subsections:
“(3) Where, pursuant to subsection (2), the whole of an unpaid amount of rates is to be taken to have become due, the person liable to pay those rates is liable to pay to the Territory, in addition to that amount, interest calculated in accordance with subsection (4) at such rate as is determined by the Minister by instrument.
“(4) The interest payable shall be calculated—
(a) on the aggregate of—
(i) the amount of unpaid rates; and
(ii) the amount of accumulated unpaid interest; and
(b) in respect of each month after the day on which the rates became due, being a month during any part of which the rates or any accumulated interest remains unpaid.
“(5) Where an amount ascertained for the purposes of subsection (3) contains a fraction of a cent—
(a) a fraction of a cent that does not exceed half a cent shall be disregarded; and
(b) a fraction of a cent that exceeds half a cent shall be regarded as one cent.
“(6) A determination under subsection (3) is a disallowable instrument for the purposes of section 10 of the Subordinate Laws Act 1989 .”.