ANZ Bank union members will be walking off the job tomorrow, after a vote earlier this week to take strike action.
The First Union said members from several of the bank's branches were striking tomorrow "speaking out against bank proposals that would be highly disruptive to family life."
Workers' key concern was a proposal from ANZ for more 'flexibility' that would leave some staff not having predictable days, start and finish times they could rely on, said Maxine Gay, Retail and Finance Secretary, FIRST Union.
"Yet ANZ is actively promoting a proposal which would leave bank workers with jobs that they cannot plan their lives around, by chopping and changing their days and start times month by month." said Gay.
She said that ANZ workers had been prepared to allow up to 20 per cent of the workforce to be flexible, but the bank wanted every new worker to start on the "insecure work contract."
The union claims it has 1324 of its members working at ANZ.
ANZ said in a statement it was disappointed that union members had voted for industrial action when a very good offer was on the table.
"The same offer has been made available to non-union staff and has met with a very positive response."
"ANZ pays its staff very competitively compared to similar jobs in the market. The salary ranges for almost all jobs covered by this agreement are the highest in the industry," the bank said.
All branches would remain open and that all banking services will be available tomorrow.