The first day of August sees what was previously IMB Mutual Building Society take on a new livery as IMB Bank.

The University of Wollongong branch will be the first to display the bank branding when it opens for business on Monday, quickly followed by all the other Illawarra branches.

IMB was approved to become a mutual bank last month and the move coincides with its 135th birthday celebrations.

Speaking from IMB headquarters on Friday, chief executive Robert Ryan said the feedback from staff and members had been very positive and the name particularly resonated well with potential new members as internet banking was attracting interest from all over Australia.

Mr Ryan said when the doors opened on Monday, existing members would notice little difference as IMB remains a home-grown, member-owned financial institution with the same range of products and services as before.

A new branch has just opened at Oran Park and more branches in Sydney, the ACT and Melbourne were expected soon as the Illawarra-born financial institution continues to grow.

"In the next few months, we will be introducing new technologies to make it easier for members to bank with us," Mr Ryan said.

The board's strategic growth plan is aimed at ensuring IMB Bank remains around for another 135 years.

At present it serves 180,000 members, has $5 billion in assets and 44 branches including more in the Illawarra than any other financial institution.

IMB has received the maximum 5-star rating from independent reviewer Canstar for eight of its competitive fixed and variable home loans, as well as a 5-star rating for their Platinum Package.

It has also granted $7.6 million to more than 500 community projects through the IMB Community Foundation.