Something that came up recently.. again...

The Land Transport (Road User) Rule 2004 states in part:

emergency vehicle means a vehicle used for attendance at emergencies and operated—

(a) by an enforcement officer:

(b) by an ambulance service:

(c) as a fire service vehicle:

(d) as a civil defence emergency vehicle:

(e) as a defence force emergency vehicle

enforcement officer means—

(a) a constable:

(b) a Police employee who is not a constable who is authorised for the purpose by the Commissioner of Police:

(c) a person who is appointed to that office by warrant under section 208 of the Act or who holds that office by virtue of the Act

Fire Authority has the same meaning as in section 2(1) of the Forest and Rural Fires Act 1977

fire service vehicle means a vehicle that is—

(a) owned by the New Zealand Fire Service Commission or a Fire Authority; or

(b) operated by the New Zealand Fire Service, a defence fire brigade, or any brigade responding under a co-ordination agreement and approved by the National Commander of the New Zealand Fire Service; or

(c) operated and approved by a Fire Authority

And also states

Use of beacons

(1) A person must not operate a beacon fitted to a vehicle unless the beacon has been approved for fitting to the vehicle, and is—

(a) a blue beacon or a red beacon fitted to a vehicle operated by an enforcement officer in the course of that officer's duty; or

(ab) a blue beacon fitted to a vehicle operated by—

(i) a customs officer (as defined in section 2(1) of the Customs and Excise Act 1996) to exercise a power to stop conferred on the officer under section 144 of that Act; or

(ii) a fishery officer (as defined in section 2(1) of the Fisheries Act 1996) to exercise a power to stop conferred on the officer under section 199 of that Act; or

(iii) a ranger (as defined in section 2 of the Marine Reserves Act 1971) to exercise a power to stop conferred on the ranger under section 18 of that Act; or

(b) a red beacon fitted to an emergency vehicle that is being operated in an emergency; or

(c) a green beacon fitted to a vehicle operated by a registered medical practitioner or registered nurse or registered midwife while on urgent medical service; or

(d) a white forward-facing beacon fitted to an emergency vehicle being operated in an emergency and that is also operating a red beacon or a blue beacon or both a red beacon and a blue beacon; or

(e) an amber beacon or a purple beacon fitted to a vehicle operated in compliance with Land Transport Rule 41001: Vehicle Dimensions and Mass 2002; or

(f) an amber beacon fitted to a vehicle operated in accordance with a traffic management plan approved by a road controlling authority; or

(g) an amber beacon fitted to a vehicle for use when the vehicle is stationary or being driven slowly and the operation of the beacon is necessary to warn other road users of a hazard due to the presence of the vehicle or of persons carrying out a lawful activity on the road in the vicinity of the vehicle.

(2) A device that allows headlamps to flash alternately may be used by—

(a) an emergency vehicle being operated in an emergency:

(b) a pilot vehicle being operated in compliance with Land Transport Rule 41001: Vehicle Dimensions and Mass 2002.

(3) The device referred to in subclause (2) may not be used during the hours of darkness.