Vancity is urging its customers to check their accounts to ensure they were not hit in the skimming operation. (CBC)A major cash-skimming operation has been discovered at a Vancouver-based credit union.

Officials say an undisclosed amount of cash has been lifted from accounts at Vancity by thieves who were able to steal debit card information and PIN numbers at an ATM or merchant terminal.

Vancity says it can't disclose the location of the compromised machine or say how much was stolen.

The credit union's spokeswoman, Karen Hoffman, said members should check their accounts to see whether money was taken.

"We would certainly encourage members to look at their accounts regularly, and follow up immediately if they spot any unusual transactions," Hoffman told CBC News.

"Also a good way to protect yourselves is to always cover your hand while punching in your PIN number because, believe or not, they still use cameras to look at what the PIN number is as you punch them in."

New bank cards with security chips will be introduced in the fall to help minimize such thefts, Hoffman said.

Vancity is now in the process of refunding the stolen cash.