TenkoFx is a relatively new broker headquartered in Russia and registered with FSP NewZealand with a physical office at Auckland. It is among large number of overseas brokers who are tryiing to benefit from flexible broker regulations of FSP in NewZeland. The physical office of Tenko in NZ was registered in Sep 2013 (after the law requiring overseas brokers to establish physical presense in NZ).
I dont see any problems with opening an account. However, the broker still has to establish repute with Forex community. As of now, there aren't many traders holding accounts with Tenko. Hopefully, someone else will be able to guide us.
Also please note that there are two distinct regulatory bodies for financial services in NZ. FSP is a registerar of corporations and any firm meeting its requirement can be registered easily. This is in contrast to FMA Home | Financial Markets Authority which is in a sense formal regulator of financial services in NZ. Whereas holding license from FMA is more privileged but FSP registeration is just as fine as numerous overseas brokers find it more convenient to meet FSP requirement rather than that of more stringent FMA.