Statistics Minister James Shaw is blaming "silly answers" for spoiling the upcoming census for the LGBT community.
Statistics New Zealand has decided to leave questions over sex, gender and sexuality out of the 2018 census, leading some activists to label the Government department as "grossly incompetent".
But Mr Shaw says Stats NZ tested adding the question in 2016 and 2017 and the quality of the information "ruled it out on statistical grounds".
"The problem is that people put down different answers and they use different language to describe the same thing," he told The AM Show on Monday.
"There's also a lot of people who, frankly, spoil the result by putting in silly answers.
"You see in the questions on religion, for example, something like 51,000 people put down that they followed the Jedi religion."
Mr Shaw says questions on religion and ethnicity went through similar "teething problems" when they were introduced. While Australia asked LGBT questions in 2016, Mr Shaw says the results weren't completely accurate.
"There is no other country that has managed to crack this in terms of getting this statistical information," he says.
The information on the LGBT community will be collected through the New Zealand General Social Survey instead.
"They do want to include it in the census, I was really disappointed that they're not including it in this coming census, so is the government's Chief Statistician," Mr Shaw says.
"Frankly it's incredible to me that it's taken this long for us to even get to this stage."
Gay rights campaigner Steven Oates told The AM Show on Monday it's hugely important to get a record of the LGBT community, even if it's not completely accurate.
"In terms of health providers, social providers, organisations like Rainbow Youth, policy decisions, you've got to start somewhere - currently there is no information," he says.
"There have been lots of organisations that have pitched to the government that this is a good thing to do, especially around gender - there is nothing about how people identify their gender in the census."
Mr Shaw agrees that marginalised people need to see themselves represented, and the information is needed to help the government effectively provide health and education services.