If the Transfer Duty is not paid within the period allowed, a penalty/interest will be payable in addition to the unpaid Transfer Duty.  

Date from% Calculated on the Duty Payable
01 January 1950 – 19 March 196312% per year calculated on a daily basis
From 20 March 1963 to 30 June 19827.5% per year for every completed month
From 1 July 1982 to date10% per year for every completed month