Support in Northern Ireland for staying in the European Union (EU) has fallen by 2%, according to a survey by Danske Bank.
Middle-class households, men and full-time workers remained most eager for EU membership.
However, older people, those in low-income households and those living in the north of Northern Ireland were more likely to support a Brexit, the bank’s chief economist Angela McGowan said.
Support for membership of the union was strongest in Belfast and the north-west.
Ms McGowan said: “The latest poll shows that there has been a very small shift when it comes to Northern Ireland’s preference for EU membership.
“Support for staying in Europe is by far the majority view, although the Leave campaigners have made a little ground over the last year.”
The poll said 56% of people wanted to stay in the EU while 18% sought an exit. A quarter of participants remain uncertain.
Ms McGowan added: “EU membership is one of the most important decisions that people in the UK will have taken in decades.
“The result will have economic, political and social consequences and it is alarming that 26% of people are uncertain about how they will vote.”
According to the study, 60% of men and 53% of women favoured staying in Europe.
Those who were unemployed or on low incomes were most likely to want UK to leave.
People in Northern Ireland still remained more supportive of the UK staying in Europe than people in Great Britain, according to the poll.
Last month Danske Bank surveyed 1,000 people across Northern Ireland on EU membership.
The proportion wanting to remain in the EU fell from 58% in June 2015 to 56% in March 2016.
Simultaneously there was a small rise in those wishing to exit. In June 2015 only 16% of those surveyed wanted to exit, with this rising to 18% in the latest poll.