For three weeks in Malaysia, I would recommend you exchange your NZ dollars to the local currency as it would then be easy to purchase items you fancy or pay for services or food as and when necessary. Not many places accept NZ$ and conversion to local currency may not be to your advantage. Best if you can change to Malaysian Ringgits in your country before you arrive, otherwise the currency exchange counters of major banks at your arrival airport (Subang International Airport) is a good place to transact money. Your visa card will be accepted at most hotels, restaurants and retail stores but not all establishment especially food courts and hawker centers accept credit cards.
Have an enjoyable here at Truely Asia! over 9 years ago