Quite; school dinners have been a source of jokes and shared misery for generations. We got breakfast, lunch and dinner at school since we lived there 36 weeks a year but the day pupils still ate lunch with us and my wife, who attended state schools, also got lunch. I do not know if that is still the case in state schools in Britain or not.
If all this is about children not being hungry, the obvious solution seems to me to be 'feed them' rather than 'rely on the parents who so far have failed in their primary duty of care by not feeding them'.
Being the socialist little island we are, food stamps are likely to not happen due to the "stigma" it causes. (though I don't care about stigma, if the result is good).
Hot lunches in school are a massive massive logistical nightmare, though the bad old days of what lunches at schools were like, are unlikely to be repeated in 2017 in NZ.
Eat my lunch is an outstanding program in NZ, it delivers nutritious lunches to kids who genuinely need it.
Rolling out on a national scale would be years in the making