Health insurance

^ differences in definition of 'healthcare'; yes there are public hospitals, but visits to a GP cost - I was paying $70 per visit in Wellington 4 years ago but costs have decreased since the introduction of Primary Health Organisations (PHO) as I see the practice I used to attend on the list attached; add $15 (2008 rate, unsure now) for a prescription from the GP, then the pharmacy charges, a dose of flu can add up.

I found this link from Wellington District Health Board, dated 19 January 2012, giving the fees - and showing the variances - for GP visits in that region

GP practice fees in the C&C DHB district

Note rates for children under 6 vary from zero to $30 per visit; $65 appears to be top rate for an adult.

^ some policies offer a percentage return, I think up to 80% but of course this is reflected in a higher premium, I had one of these policies for years an doubt I came anywhere near recovering the fees I paid (their ideal client!), I cancelled with a change of employer that had an employee scheme, I joined for 50% refunds for a minimal weekly fee.
With a family/children I'd suggest you get a few online quotes and do some calcs of your own re cost/benefit. Also check on existing conditions and whether they are covered eg asthma medication.