Four hundred jobs are expected to be created at a call centre in Armagh, in a €10.5 million investment over the next three years.
Telemarketing company AnswerCall Direct is building offices in the city to meet growing demand. It employs 300 in nearby Portadown.
Managing director Mr Kelsey Buck said AnswerCall's ambition was to become one of the North's leading outsource contact players.
"We aim to achieve this by investing in the latest telecommunications technology and leading industry customer relationship management systems. This will enable us to deliver a consistently high-quality service that adds significant value to the operations of our customers," he said.
The expansion project is grant aided by the North's Enterprise Trade and Investment department. Minister Mr Ian Pearson said the company's success was an example to other local entrepreneurs.
"This is a first-class example of an entrepreneurial company which is experiencing fast growth in the intensely competitive contact centre marketplace through an ongoing commitment to excellence in the services it provides to customers," he said.
"It [the expansion\] will also strengthen the skills base in Armagh by providing opportunities to local people to gain experience and expertise in customer-focused telemarketing services."