PORTLAND – Banks and credit unions across Maine are issuing tens of thousands of new debit cards to customers whose card numbers may have been compromised by a hacker who stole customer data from the parent company of T.J. Maxx and Marshalls stores.

TD Banknorth, a regional banking company based in Portland, said it is issuing new cards to as many as 200,000 customers in eight states as part of the continuing fallout from the security breach at Massachusetts-based TJX Cos.

Most other Maine banks and many credit unions have also reissued debit cards or are in the process of doing so.

Chris Pinkham, president of the Maine Association of Community Banks, estimated that tens of thousands of cards and personal identification numbers are being replaced in Maine. But the process has taken time because so many cards need to be replaced nationally that supplies have been running out, he said.

“Nobody has thousands of cards in stock,” he said. “Banks had to order them.”

Banks have been scrambling nationwide to issue new cards to customers after the discovery of the security break at TJX Cos., which owns T.J. Maxx, Marshalls, A.J. Wright and HomeGoods stores in Maine.

Joe Pietroski, president of the Maine Bankers Association, said it costs between $12 and $22 to replace each debit card, including the cost of notification. That’s a big expense for smaller banks, he said, and in some states banking groups are pushing for legislation to require retailers to pick up the tab.

No one can estimate how many Mainers’ cards may have been misused because the information is confidential.

TD Banknorth hasn’t seen an uptick in irregular charges, according to Leslie Roberts, an assistant vice president for corporate communications. Customers aren’t liable for fraudulent charges on their cards, the bank has said.