Referendum is a method of direct democracy that allows citizens to vote on specific issues. Unlike elections that focus on selecting representatives, referendums allow voters to directly decide on policies or proposals, with outcomes that can be binding (and sometimes even mandatory).
A referendum can be initiated either by the government or by citizens. Government initiated referenda are typically on major political issues and may be binding, although these types of referendums are less common than citizen initiatives. Government-initiated referendums are often held when a governing party is divided over an issue, for example the 1975 UK referendum on European integration (which was not legally binding).
A citizen initiated referendum can be non-binding and can be held at the same time as a general election or at a stand-alone poll. Usually, the government will pass legislation to enable the referendum, including setting out the wording of the question and rules for campaigning. The rules will usually include limits on the amount of money that can be spent on advertising for or against the referendum, and will provide for a process to decide how the question should be framed.
Once a referendum is endorsed, the New Zealand Electoral Commission runs it just like an election. This includes setting a date for the referendum, providing voting centres and overseas voting centres, and distributing a pamphlet that contains arguments for and against the proposed change. The pamphlet must also contain unedited statements from groups that support or oppose the proposal.