Copies of the original Stamp Duties Act can be found here, click Stamp Duties Act (Cap. 68) (Consolidated Edition 2006). Please note that it has been subsequently amended. The amendments can be found in here:
Stamp Duties (Amendment) Act No. 26 of 1988
Stamp Duties (Amendment) Act No. 32 of 1989
Stamp Duties (Amendment) Act No. 40 of 2006
Stamp Duties (Amendment) Act No. 40 of 2006