Members of the First Union were protesting outside a bank branch in George St yesterday, part of a national strike, over a proposal they say would mean workers only knew their working hours month to month.
But the bank questioned their claims, and how many protesters were actually ANZ staff.
Union organiser Shirley Walthew said the workers had been involved in negotiations with the bank since last month, and had been offered a wage increase of 2% to 3%.
But the call for flexible hours was a sticking point, and 96% of union members had rejected the bank's offer.
At present, most employees had fixed hours between 8.30pm and 5pm.
Changing that would have an effect, Ms Walthew said, ''because a lot of our members have children, they are studying, they have outside activities''.
The bank responded yesterday it was disappointed the union took action when ''a very good offer was on the table for our staff''.
Senior communications manager Stefan Herrick said customers wanted some branches open later on some evenings or on Saturdays and Sundays, so staff were needed to work at those times.
''Instead of a staff member having to work every Saturday/Sunday, we want to be able to roster them to take turns.
''We think this is fairer, but can't do this under our current agreement.''
Mr Herrick said days or hours of work would not change every four-week period.
Instead, they would only change ''from time to time, where needed'', due to influences such as changes in customer demands or to cover for other staff who might be on leave.
He also questioned the turnout at protests nationally.
''A large number of the protesters were union officials or supporters - not ANZ staff,'' he said.
All branches had remained open and all banking services were available to customers during the industrial action.
