"More investors are buying rental properties because there's no capital gains tax and also because times around Northland are tough which means people can't hold on to second homes," Mr Hickey said.
He said there were more poor people without their own homes and a few rich residents who continued to invest in rental properties.
The Census also pointed to Northland having the second highest rate of te reo Maori speakers and Maori population after Gisborne.
Nearly one third of the 151,692 Northlanders identified themselves as Maori, although their numbers in the Far North, Whangarei and Kaipara have fallen since 2006.
There are 7449 Maori speakers in the Far North compared with 7914 in 2006. Whangarei has 4347, down from 4578, and Kaipara 813 in comparison to 963 seven years ago.
Labour list MP Shane Jones, who over the years pushed for Maori to be registered, said he feared a large number did not fill out the Census form, probably because of aversion to paperwork from the Government.
"That's disappointing because those figures are used for the allocation of resources. We see a similar pattern of disengagement in local government and parliamentary voting."
Figures also show that the number of houses with internet access in Northland increased from 26,433 in 2006 to 36,855 this year.
Whangarei had the biggest increase, from 14,323 to 19,848 homes, followed by the Far North at 12,183 compared with 9003 in 2006, and Kaipara up from 3195 to 4827.
Small increases were also noted for use of cellphones and other telecommunication devices over that period.
In terms of population movement since 2006, Northland registered an increase of 3222 - from 148,470 to 151,692.
Far North was the only area in Northland that saw a drop in population - from 55,845 in 2006 to 55,734 this year.
Whangarei, at 76,995, has 2535 more people this year than in 2006 when there were 74,460 residents.
Similarly, population numbers in Kaipara went up, from 18,135 to 18,960 over the past seven years.