Who can initiate an optional referendum at the national level?

Cook Islands
- Government
- Legislative majority
The Constitution of the Cook Islands is at: http://www.parliament.gov.ck/Constitution.pdf
The Constitutional and Other Polls Act 1993 is at:
For constitutionally mandated referendums, the proposal must first receive a legislative super-majority: Constitution of the Cook Islands sections 37(7) and 41(2).
For optional, advisory referendums (aka polls) the Prime Minister and Cabinet may simply order such a poll: Constitutional and Other Polls Act section 4.