The fire, which started at approximately 1 a.m., damaged a small section of the roof, but was quickly extinguished.
Smoky smell
Normal operations at the branch were still interrupted because of the smell of smoke in the building.
The cause of the fire is still under investigation.
"We recognise the difficulties that the reduction in service has caused our members and we have taken the necessary steps to provide them with alternatives, at our Half-Way Tree location," said Hugh Reid, senior vice-president and chief operating officer at VMBS.