- The [Government] [Substituted by the A.O. 1937 for "Local Government "] may, [after consulting the authority appointed under the section 36] [Inserted by Act 6 of 1916, Section 7.], exempt, [subject to such conditions, if any as it thinks fit to impose, any vessel one class of vessels] [Substituted by by Act 6 of 1916, Section 7, for "the vessels "] entering a port subject to this Act from payment of port-dues and cancel the exemption, or may vary the rates at which port-dues are to be levied in the port, in such manner as,.having regard to the receipts and charges on account of the portrait thinks expedient, by reducing or raising the dues, or any of them [or may extend the periods for which liability to pay port-dues] [Inserted by Act 6 of 1916, Section 7.]:

Provided that the rates shall not in any case exceed the amount authorized to be taken by or under this Act.