Aucklanders may struggle to get money out of ATMs today, with the security guards responsible for their upkeep going on strike.

The Service and Food Workers Union claims banks are receiving record profits while screwing down contractors.

More: NZ banks record $3.3 billion dollar profit

It comes after months of failed attempts to get more pay for crew leaders.

The Service and Food Workers Union spokesperson Jill Ovens said banks are trying to cut the fees for security guards to pick up money from ATMs - meaning security companies don't have huge margins to pass on to workers.

She said that's disgusting, because if security guards weren't risking their lives in the dangerous job of transferring money the banks would be in trouble.

"I find that quite disgusting actually, because if our guys went out there, risking their lives to get this money in so that it can be processed, the banks would be in real trouble, what would they do?"

Ovens said in Australia, guards are armed - here they rely on their wits and have to keep alert to any possible attempt to snatch money from them during transfers.

She said the crew leaders have huge responsibilities in a dangerous job.

"They have somebody else driving with them. and they're responsible for that person's safety as well as their own, and of course for the millions of dollars that they're carrying."