Hundreds of ANZ workers around the country are walking off the job again today.
First Union members have rejected the Bank's offer of a 3 percent rise this year and 2.7 percent increase next year.
They are also fighting ANZ's attempts to change the days and hours staff will work each month.
ANZ said it is just responding to customer demand to be open longer and on the weekends.
But First Union's retail and finance secretary Maxine Gay said ANZ doesn't have to change the collective agreement to do that.
"Already the bank can employ people for example Tuesday to Saturday, or Sunday through Thursday. The bank already has the ability to meet customer demand and that's evidenced by the fact that the bank made $1.37 million in profit."
Maxine Gay said the proposed changes would make it particularly hard for staff with families to arrange childcare.
Bank staff have also filed legal action against their employer, saying the bank has breached the Employment Relations Act.
ANZ said it will meet with the Union early next month to discuss the legal action being taken and employment issues.
About 500 bank staff took strike action earlier this month. They also protested against the $4.1 million salary of ANZ chief executive David Hisco who is the highest paid executive in New Zealand.