Well, that's another problem with how they went about it. If you're going to muck about with changing the electoral system, you really need to make an effort to get people involved, and consider all the possible systems. This referendum seemed to come out of nowhere, with only one option for the new system. It wasn't clear who it was who decided that this MMP system was the only other choice we'd have, and why they chose it.
Blindsiding the electorate really isn't the way to go about fixing things.
This is very true, when we changed there was a lot of frustration with the FPTP system as while many people were turning to vote for third parties, they weren't getting in and instead we had just been through three terms were Governments held majorities in the house but had way less than 50% (if I recall right about 35-40%) of the vote, and then proceeded to ram through things that the majority of the country opposed.
We had two referendums. The first, held on 19th September, 1992, asked a) did we want to change, and b) if we were to change, which system we would prefer to change too, and then a second. While only 55% of the country voted (referendum outside of elections tend to have low turnout) 85% of those that did (including me) said change, and the system that won that was MMP, which got 70% of the vote.
Previous to that there had been a lot of advertising and explanation of the systems, though some supporters of non-MMP systems felt that MMP had been given an unfair advantage by several lobby groups.
The second referendum was held at the same time as the 1993 election, so garnered a greater turnout, 85% of voters, and it asked for a straight preference between FPTP and MMP. MMP won 54% to 46%.
This was confirmed in an follow up referendum last year at our 2011 elections. Again there were two questions, should we retain MMP, and if not, which system would you rather have, This time (though voter turnout was lower) MMP gained 57.7% of the vote to retain, though FPTP was the favoured of the alternative systems (it got 46%.)
Again there was a lot of advertising, pamphlets, and even a website to help explain how they all worked.
For more info....
http://www.elections.org.nz/voting/mmp/history-mmp.html
http://en.wikipedia.org/wiki/New_Zealand_voting_system_referendum,_2011