Just to take out of those "Commonwealth figures: at the start of World War One the total population of New Zealand in 1914 was just over one million.In all, 120,000 New Zealanders enlisted, of whom 103,000 served overseas. A total of 18,500 New Zealanders died in or because of the war, and nearly 50,000 more were wounded. Of the total number who died, over 2700 died at Gallipoli, and 12,500 died on the Western Front.
That represents a casualty rate of 66 per cent; huge given the size of the population. My understanding from my own family, or rather my wife's family, is that there was never any question of not going to serve "King and Country", but NZ paid dearly for it.