A survey of Chamber of Commerce members in Northern Ireland suggests that 81% will vote for the UK to remain in the European Union (EU).
A referendum on the UK's membership of the EU is to be held later this year.
The survey indicates that only 11% of of the chamber's members in Northern Ireland support a British exit (Brexit).
That compares to 30% of those surveyed in the rest of the UK.
The Chamber of Commerce has about 1,200 members in Northern Ireland.
About 250 of those responded to the poll.
More than half of the respondents (60%) said that Prime Minister David Cameron's renegotiated EU deal is unlikely to change how they will vote.
The results come on the eve of crunch Brussels talks, which are expected to result in a deal.
Eighty-four per cent of those surveyed in Northern Ireland also say that there has been no impact on their sales and orders as of yet, due to the uncertainty of Britain's future within the EU.
Commenting on the results, President of Northern Ireland Chamber of Commerce Stephen McCully said the findings suggest that "the renegotiation is having little impact on day-to-day business - or the vote of the business community".
He said that this was because many made up their minds before knowing the outcome of negotiations, effectively discounting them as irrelevant.
"For businesspeople, this is a question of in or out," he said.
"Those within Northern Ireland who are firmly wedded to the EU have said that Brexit will leave us stranded outside the EU, and coping with the re-emergence of a land border with the Republic of Ireland.
"Emotion has a part in all decision making and it will do so here, but there is a duty to ensure decisions are as well informed as they can be."
Clarification: An earlier version of this article omitted the number of respondents to the Chamber of Commerce survey.