Defence sales last year were worth £128 million to Northern Ireland businesses.
Missiles, military clothing and covert technologies are all produced in the region, a report said.
The report added that Thales, with a major facility in Belfast specialising in short-range complex weapons and launcher system, is the largest company in the defence sector.
Thales and the MoD recently announced a contract for the development of lightweight multi-role missiles.
The security industry is also experiencing strong growth, the survey by the Aerospace Defence Security (ADS) group added.
ADS Northern Ireland chairman David Beatty said: "The defence sector is facing some challenges as a result of the UK strategic defence and security review. However, the sector is competing hard and winning both MoD business and orders from export markets."
A total of 7,541 people are employed in the aerospace, defence and security industry in Northern Ireland, almost 10% of those working on defence.
Under the strategic defence review announced in October, defence spending is set to fall by 8% over four years.
With the local industry benefiting from MoD contracts, it was reported in April that the MoD has won a reprieve on its £1 billion funding gap this year. The Treasury and MoD have agreed on measures to be taken this year.
According to the ADS report, security sales by Northern Ireland companies were worth £11 million, but it said the actual figure was likely to be much higher. A 14% increase in UK exports has been recorded.