There are no restrictions on receiving a salary from outside New Zealand — however, you will need to file a New Zealand tax return on all income.
Transferring money internationally is simple — New Zealand banks are set up to wire money almost anywhere in the world. You can even do it over the internet or phone. Check your bank for details.
Most NZ banks take quite hefty charges for transferring to/from New Zealand, so if you’re planning to transfer money on a regular basis, perhaps from a savings account or overseas pension, then you should consider a company such as NZForex as they charge a fixed fee and are very reasonably priced. Even better, NZForex transfers can be completed entirely online which makes life much simpler.
Western Union offices are also available in Auckland if you prefer to deal with a person over a counter instead of via the Internet.