Its cheques were not legal tender and could not be used to pay debts.
"There will be no joy for anybody who thinks they are on to a winner with a WeRe bank cheque book.
"It sounds too good to be true, because it is."
Sladden said this was the first complaint it had dealt with in New Zealand but there had been other cases in the UK and Canada.
British regulator the Financial Conduct Authority has also issued a warning about the bank.
Sladden said people who tried to use the cheques would face all the normal risks of late payment from additional charges to repossession.
In the case of the New Zealand woman the bank refused to honour the cheque and then closed her account after its relationship with her deteriorated.
A complaint was then made about the bank's decision to refuse the cheque and whether it could end the relationship with her.
The Ombudsman determined that the bank had the right to end its banking relationship with the customer and had followed the correct process for doing so.