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.
"Most of the people convicted were charged with two offences: failing to fill out the individual form and the dwelling form. The fines ranged between $50 and $500 per charge," he said.
"Before prosecuting we took into consideration the type of offence, the personal circumstances of the person, and the likelihood of success. We also encouraged people to complete their census forms before going to court.
"Everyone in New Zealand on census night is legally required to complete a census form. The information is used to make important decisions on which public services are needed ? such as hospitals, schools, and roads ? and where they should be."
"Census and all Statistics NZ surveys depend on everyone taking part and providing accurate information. Prosecution is our last resort."
After the 2006 Census, Statistics NZ filed 72 cases in the District Courts, resulting in 41 convictions.