33. (1) Subject to the provisions of sub-section (2), in each of the ports mentioned in the first schedule such port-due, not exceeding the amount specified for the port in the third-column of the schedule as the Government directs, shall be levied on vessels entering the port and described in the second column of the schedule, but not oftener than the time fixed for the port in the fourth column of the schedule.(2) The Government may, by notification in the official Gazette, alter or add to any entry in the first schedule relating to port in Bangladesh ¹[* * *] and this power shall include the power to regroup any such ports. (3) Whenever the Government declares any other port to be subject to this Act, it may, by the same or any subsequent declaration, further declare,- (a) in the terms of any of the entries in the second column of the first schedule, the vessels which are to be chargeable with port-dues on entering the port, (b) the highest rates at which such dues may be levied in respect of vessels chargeable therewith, and (c) the times at which such vessels are to be so chargeable. (4) All port-dues now leviable in any port shall continue to be so leviable until it is otherwise declared in exercise of the powers conferred by this section. (5) An order increasing or imposing port-dues under this section shall not take effect till the expiration of sixty days from the day on which the order was published in the official Gazette.