Gem is based in in Lanyon Place, Belfast

A number of the posts at Gem will be part-time, but the company said a proportion are likely to be converted to full-time posts.

The Belfast-based company is also opening an office in Hungary, employing initially about 80 people.

Managing director Philip Cassidy said revenues have increased by 40% this year.

He told Good Morning Ulster the work was coming from a variety of areas.

"Some of it is Play.com, which is one of our major contracts, some of it is Cisco, Expedia and Microsoft so we have a number of different clients out there that require additional capacity," he said.

He said they had also signed up McAfee, the internet security company, and a gaming company.

Mr Cassidy said that in the contact sector there seemed to be a move back to Europe from Indian contact centres.