The Central Government may, after the due appropriation made by Parliament by law in this behalf, advance to the Small Industries Bank--
         (a) an interest free loan of such amount and repayable in such instalments and in such other manner as may be determined by the Central Government; and
         (b) such further sums of money by way of loan on such terms and conditions as may be agreed upon:
     Provided that the Central Government may, on a request being made to it by the Small Industries Bank, increase the number of instalments or alter the amount of any instalment or vary the date on which any instalment is payable under clause (a).