I've done some research about driver's licenses in the past. New Brunswick is the only province that didn't publish (findable) information on their website. Most provinces offer at least 90 days of driving with your class 5 equivalent driver's license, often longer in combination with a International Driver's License (IDL). They website says you can get more information at your local New Brunswick Service Desk.
In many provinces it is 90 days. In Ontario it is 60 days. Temporary residents with an international license can sometimes drive for longer.
According to http://www.onestopimmigration-canada.com/driving_in_new_brunswick.html it is only 10 days in NB and according to http://app.infoaa.7700.gnb.ca/gnb/Pub/EServices/ListServiceDetails.asp?ServiceID1=200843&ReportType1=ALL you must obtain a New Brunswick driver's licence as soon as you take up residence.