sentences:  It is often referred to as the NHI, although care must be taken when using this abbreviated term, because the NHI can also refer to the national collection of health care user demographic data (of which the NHI Number is the unique identifier).The NHI Number, as part of the NHI was established in 1993.Primarily the NHI is used to identify individuals uniquely within the New Zealand health system, especially in electronic systems.