That means the bank must wait to cash the payment until the date stated on the paper or until six months is up, whichever comes first. A "post- dated cheque" is only a bill of exchange when it is written or drawn, it becomes a "cheque" when it is payable on demand. The Commonwealth Bank of Australia 's rules and conditions for cheques However, a bank may refuse to honour a cheque if the post-date is noticed; otherwise, the payer has no right to take any form of legal action against the bank for letting the cheque be processed. If a Canadian financial institution inadvertently accepts and processes a cheque before the due date, the cheque writer may ask his or her financial institution to return the amount until the day before the cheque should have been cashed. Try again later Consumer Support. The only way to possibly prevent a postdated check from being processed early is to let everyone involved know in advance — and in a format that goes beyond just postdating the check.