Statistics New Zealand says Maori communities may be missing out on funding for essential services, because not all families fill in the census forms as they're supposed to do.
Community liaison adviser Luke Crawford says the more than 2% of Maori didn't fill in forms in the last census in 2006.
He says they need to understand that the information gathered is vital when government departments or councils are making decisions, about the provision of everything from children's health services, schools, Maori arts and culture centres and recreational facilities.
Mr Crawford says he was recently in Te Araroa on the East Coast and spoke to a council worker about how the local sewerage system has been renewed based on information from the last census.
He says he and other liaison advisers are happy to give advice to Maori families in either English or te reo, about taking part in the census on Tuesday 5 March.