Manager of the Newry Street branch, Paul Robinson, said there would be redundancies in the long-term but at present all staff will be moved to Portadown.
Mr Robinson said he wanted to thank all customers who have used the Banbridge office.
"We hope customers from Banbridge will now use our Portadown office and we can guarantee the same high quality of service they are used to," he said.
The Lurgan office is also relocating to Portadown and Managing Director Libby Clarke said the time was right to restructure the company into one head office.
She said, "It makes more sense to relocate and consolidate our business to Portadown where we own the office rather than sustain the overheads on three offices."
She added that Portadown's West Street office was a very large building with plenty of space to accommodate the restructuring, and that there would be no reduction in the high levels of service already available to customers.
She refused to be drawn on the subject of redundancies, pointing out that there were due processes to be followed.
Another factor in the decision to restructure, she said, was the "massive swing" towards searching for properties online. "It's a thing of the past for people to take time off work to talk to estate agents in an office.
"Most viewings are done at night and on a good week we get 7,000 to 8,000 visitors to our internet site, taking virtual tours of houses and arranging viewings.
"In many cases we do not meet a buyer until they have agreed a sale and are leaving in identification and other paperwork."
As to the current downturn in the property, Mrs Clarke said, "There's no doubt people to a certain degree are not sure whether it's the right time to buy. There are a number of potential buyers keen to move but they are hesitant, mainly due to press coverage on rising living costs such as fuel.
"However, our level of sales can easily sustain one branch and associated costs."
The closure of the Banbridge and Lurgan offices is due to take place within weeks.