Bank workers' union Finsec says banks need to review security following a spate of armed robberies in Auckland.
In the past week, there have been six hold-ups in the region and about 25 nationwide this year.
BNZ says that between 2000 and 2006 there were about 20 robberies a year and it expects numbers to be closer 60 this year.
Finsec spokesperson Andrew Campbell is partly blaming the increase on the recession and the fact that people are seriously strapped for cash.
Mr Campbell believes a bank security review is in order, saying it has been a decade since any major changes were made.
The union will meet with a some banks this week to discuss the issue.