The investment also includes improvements to branches and infrastructure and the introduction of a range of new positions.
This includes a number of roles at its wholly owned subsidiaries including Newcastle Strategic Solutions.
A total of 50 new roles have been made available with immediate effect with a further 50 to be made throughout the year.
Chief executive Andrew Haigh said: “Our strategy is to provide long-term member value and be a strong modern day, regional building society.”
In addition to improving its physical presence in the region, the society’s investment programme also extends to continued development of its digital services and telephony systems.
A new website, which will launch shortly, will also include greater mobile functionality and more interactive financial content.
Haigh added: “This investment programme recognises the importance of offering members the choice of both digital and a modern and effective branch network.
“It is a long term commitment to help ensure that we can continue to offer our customers an excellent, face-to-face service within the communities in which we operate.
“This is a positive step for Newcastle Building Society as we continue to invest in developing our products and services to meet the changing needs of our customers.”
Summarising the plans he said: “This is an exciting time for Newcastle Building Society as we build upon the tremendous progress we have made throughout 2015 and we look forward to welcoming new staff to the society team as we deliver these plans through 2016.
“This programme of investment will enable us to continue to provide excellent service and good value products to our members, who own the business, with increased choice as to how they engage with us, including a much improved branch network and digital offering.”