Westpac confirmed earlier this month it would leave the building it's occupied for a century on the corner of Macquarie and Church streets, and move in with St George later this year.

The group's two brands will operate under its new "co-location" model, being rolled out at eight regional centres.

The two-branch model will incorporate both brands, side by side, and will be staffed and serviced by local teams from both brands, a Westpac Group spokeswoman said.

"This will help ensure both brands retain a clear physical presence with the same face-to-face service and connection to the community," she said.

The new arrangements are due to officially open in early October.

Earlier, Westpac said the change would help it retain a face-to-face service at a time when customers are choosing to visit branches less.

It also confirmed there would be no impact to employees of either branch.

The Finance Sector Union labelled the decision "disappointing" and forecast the co-location would present some challenges and it would work closely with its members during the time.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: