SBS chief executive Wayne Evans said the damage could cost about $50,000.
‘‘I'm hoping our customers will be patient, but with digital technology I don't think this would have affected business.''
All but a skeleton staff were sent home for the day. The bank was expecting to open as normal on Monday, he said.
A New Zealand Fire Communications spokesman said two fire crews attended and entered the building wearing breathing apparatus.
The fire was out by 10:05am, at which time another crew used large pumps and fans to ventilate the smoke.
No injuries were reported, he said.
The cause of the fire is being investigated.
-by Jono Edwards