Two banks are blaming each other after an ATM receipt showed a Gold Coast woman she had almost $10 million available to spend on her credit card.

Sue Lamb was shocked to have the money apparently appear in her bank account on Sunday, posting to Facebook on Sunday posing with cash and joking about a trip to Tahiti.

Sue Lamb celebrates her surprise $10 million windfall. ANZ said the figure wasn't her available balance. Credit:Facebook

"Just checked my credit card which has a limit of $50k and guess what!" I'm a millionaire!" she posted.

"Check out the balance. Plus I've got no debt on it sooo strange.