The company already employs 1,000 at its base in Londonderry and 400 in Belfast. In May 2008, it had created 800 jobs, which was widely hailed in the region.
Firstsource is among a growing number of Indian companies like HCL, Polaris, PixTransmission and Tech Mahindra who have chosen to set up offices in the region that was, until recently, known for violence.
Firstsource general manager Sean Harnett said Londonderry had a lot to offer the company and they were very happy with its staff in the city.
He said: "There is a great work ethics here and good employees, and we find people will work very well with us and are committed to what we are trying to achieve. We have some fantastic people working for us and we have been very happy with what we have found here."
The company has 21,000 employees working from 43 centres in India, the UK and USA, as well as Argentina and the Philippines.
It has been widely noted in the region that the Indian company's expansion is in contrast to its neighbouring call centre company in Londonderry, US-owned Stream International, which is expected to slash nearly 450 from its workforce.
The development further enhances the strong links between Northern Ireland and India which has led to a string of inward investments from Indian companies. To further cultivate these links, Invest Northern Ireland, an official agency, has opened an office in Mumbai.
Alan Hingston, Invest Northern Ireland's director of trade, said: "India is fast becoming a key market for Northern Ireland companies across a range of sectors including IT, biotechnology and consumer products".
He added, "Initiatives which we are planning will provide additional support to companies to seize the massive business opportunities in what is now one of the world's most dynamic markets."
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