Lets get real people, it is a quantum leap between the Defence force assisting Police to Martial Law. The NZ army and Navy assisted with Christchurch, Kaikoura and also Napier and this did not mean martial law. I am aware that my comments will now attract the usual sniping but talk of martial law is scare mongering and not at all helpful.
I wouldn't get too wound up with definitions - ie calling it "martial law" or whatever.
The NZ Army more than merely "assisted" after the Chch quakes, they set up and maintained road blocks around red zones, with army trucks and armed soldiers very visible. What was at risk there was property (preventing looting) and preventing complete morons from trying to retrieve their own property in a haphazard manner from buildings that were at risk from collapsing with constant aftershock activity. The level of civil disobedience to something sensible was unbelievable. High profile business people were boasting in the media about how they'd been able to get into their offices to retrieve stuff - that they decided was more "important" than the common good.
There's much more at risk here. Expect to see a very visible army presence.