Clause 21

Where any postage or other fee or sum is not prepaid or fully prepaid in respect of a postal article posted for delivery in Singapore, a public postal licensee is entitled to be paid, as a condition of delivery, such fee, in addition to the amount of the postage or of the deficient postage payable in respect of the delivery of the article, as is payable in accordance with a determination made by a Postal Authority.

The official mark or label on a postal article denoting that any postage or other fee or sum is due in respect thereof to a public postal licensee or to the postal authority of any foreign country shall be prima facie evidence that the postage or other fee or sum denoted is so due.