The Banking Ombudsman is warning about the perils of high-risk online trading.
There have been complaints from people who want refunds for credit card payments they have made to websites where they traded what are called binary options, a high-risk form of investment. People speculate on whether shares, currencies or commodities will rise or fall in value.
The Financial Markets Authority says the options are risky, for even experienced investors. The advertising for the sites often makes the trading look easier than it really is.
Banking Ombudsman Nicola Sladden says the complainants wanted the banks to refund them for the credit card payments they had made to the sites. But she says you can't expect to be reimbursed for authorised payments.
"Bank customers complain to us that banks won't arrange the return of the money. But the fact is, banks can't do that because the transactions were authorised by the individuals themselves.
"The payment process was perfectly correct. It was the investment that was unsound, and banks cannot be held to account for that.
"It's a case of buyer-beware."
The online platforms are often overseas based and are therefore not regulated by the New Zealand authorities. It raises the issue of whether some of the sites might be scams.
The Bankers Association is backing the Ombudsman's advice.
The association's chief executive Karen Scott-Howman says: "Once you've authorised an online payment with your credit card to a binary options trading website, you can't expect to get a chargeback if the trade doesn't go your way."
There are situations where people are entitled to a refund or chargeback on their credit card.
Chargebacks may occur in cases where the payment was not authorised by the card holder, or the goods were either not received or defective, or if the payment was incorrect or duplicated.
The Banking Ombudsman scheme has more information on its website about credit card chargebacks.