Legal provisions for optional referendums at national level

Constitution of Jamaica
(Adopted 1962, last amended 2011)
http://pdba.georgetown.edu/Constitutions/Jamaica/jam62.html

Electoral Commission (Interim) Act
(Passed 2006)
http://www.moj.gov.jm/sites/default/files/laws/The%20Electoral%20Commission%20%28Interim%29%20Act%20pdf.pdf

As specified in Section 49.6 of the constitution, thelower house can call an optional referendum if it passes a bill that amendsconstitutional provisions specified in 49.2 and 49.3, but the same bill failsto pass the Senate.