More than 40 people ended up with criminal convictions after they refused to fill in their census form, Statistics New Zealand says.
SNZ said 450 people received a letter asking them to complete their census form or face prosecution in July 2013.
After this, 99 cases were filed in the District Courts and 46 people were convicted.
Census Manager Gareth Meech said that of the 99 cases, 39 people filled in their forms and their charges were dropped.
Two people were discharged without convictions and 12 people were not able to be served with their papers.