Legal provisions for optional referendums at national level

The Constitutional Act of Denmark (1953)

42. (8) Rules for referenda, including the extent to which referenda shall be held in the Faroe Islands and in Greenland, shall be laid down by statute.

See also: 

Act on Greenland Self-Government (2009)

The Greenland Home Rule Act

Constitution of Denmark provides for the possibility of referendums in Greenland. However, no statue has been found to regulate this matter.