Who can initiate an optional referendum at the national level?

Law on Referendum (1995, last amended in 2008)

http://aceproject.org/ero-en/regions/asia/KZ/kazakhstan-constitutional-law-on-referenum-1995/view

Article 11. Initiative to appoint the republicanreferendum

1. The initiative to appoint the republican referendumbelongs to:

1) President of the Republic of Kazakhstan;

2) Parliament of the Republic of Kazakhstan, whichshall request the President of the Republic of Kazakhstan to appoint areferendum. Submission of the initiative shall be carried out by the Parliamentat separate sessions of the Houses by consequent consideration of the issuefirst in Mazhilis and then in Senate and shall be issued by the relevantresolutions of Parliament Houses;

3) Government of the Republic of Kazakhstan, whichshall request the President of the Republic of Kazakhstan to appoint areferendum. Submission of the initiative shall be carried out by the Governmentat its session by the majority of votes of the total number of its members andshall be issued by the relevant resolution;

4) at least by 200 thousand citizens of the Republiceligible to take part in the republican referendum, who quantitatively andequally shall represent all oblasts, capital of the Republic and city of therepublican status, who shall request the President of the Republic to appoint areferendum.