The poll findings indicate that people's sense of national or cultural identity is shifting, particularly among Catholics. The Northern Irish identity is weakening, perhaps in response to years of unrest.
Respondents were asked whether the term Northern Irish, Irish or British best described them.
The figure excluding undecided (20.9%) is given in brackets.
Northern Irish got the support of just 13.3% (16.9%) of the sample, Irish was the chosen identity of 20.5% (25.9%) and British was chosen by 33.4% (42.2%) with 11.9% (15.1%) giving some other identity.
This is higher than the actual immigrant community in Northern Ireland.
There was a fall in the number of people giving their identity as Northern Irish (16.9% excluding undecideds) compared to the census (20.94%). But the fall may also be due to events since March 27, 2011, when the census was taken.
At the end of last summer marching violence broke out, last winter we had the flag protests and as the poll was being taken there were further marching disturbances.
This may have contributed to a fall in identification with Northern Ireland without increasing the appeal of Irishness. There were also signs of shifting national identity among Catholics.
Just over 25% who identified as Catholics also described themselves as British, slightly less than the 27.5% choosing Irish but far more than the 16% of Catholics who counted themselves Northern Irish.
The census found that 59.11% of people, (well over the Protestant population) held a British passport compared to 18.9% who held an Irish one.
The only social group where Northern Irish was the favourite designation was the higher AB social classes, 27.8% of whom chose the designation compared to British (24.4%) and Irish 19.9%.
Almost half (48.8%) of people in lowest income DE grouping described themselves as British compared with 21.4% Irish and 6.9% Northern Irish.