The Central Statistics Office has said the decision to include only five religions by name in its Census 2006 questionnaire was made on the basis of the results of a public consultation process in late 2003.
As part of the consultation in November 2003, the CSO invited submissions from the public and interested parties on what they wanted in the 2006 census.
The consultation resulted in a pilot census taken up in April 2004 which excluded a question on religion to facilitate the inclusion of new and revised questions on ethnicity, disability, unpaid work and voluntary activity.
Eighty submissions from Government departments, State agencies, local authorities, the research and academic community, and private individuals were received.
The religion question on the 2006 questionnaire has remained unchanged from the 2002 census. It lists Roman Catholic, Church of Ireland, Presbyterian, Methodist, Islam, other and no religion as possible responses.
There is a space beside "other" to write in a religion that is not listed.
A spokeswoman for the CSO said yesterday that "everyone's religion is counted", but added that publishing constraints limited the extent of possible responses. She said there would be another public consultation process in advance of the 2011 census and that historically the CSO had expanded the number and types of questions in its population survey.