Forty-six people are out of pocket up to $500 for not filling out their census form.
Statistics New Zealand said it wrote to 450 people in July 2013 asking them to complete their census form or face prosecution.
But 99 people ignored the request and had cases filed in district courts, resulting in 46 convictions.
Census Manager Gareth Meech said most people were charged with two offences: failing to fill out the individual form, and failing to fill out the dwelling form, and received fines.
"The fines ranged between $50 and $500 per charge.
"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."
Out of the 99 cases, 39 people complied with that request and subsequently their charges were withdrawn, he said.
"Prosecution is our last resort.
"Having reliable population data helps with planning and building the infrastructure that communities need to succeed, and this benefits everyone."
After the 2006 Census, Statistics New Zealand filed 72 cases in the District Courts, resulting in 41 convictions.