There is also ACT New Zealand and United Future with one seat each.
There is a 5% threshold, but it doesn't apply to parties winning an electorate (through doesn't really apply to ACT and United Future because .66% and .21% doesn't gave any proportional list seats anyways, even without a threshold).
Odd that United Future can win an electorate on 0,2%, it must be an extremely small one, do they have very uneven electorates?
Clearly unfortunate that Conservatives can get 4,1% without representation and two parties get in with less than 1% (and less than 1/121 of the votes).
A quick skim of Wikipedia indicates no major differences in population between electorates. United Future's leader, Peter Dunne is their only candidate who garners significant votes. Think of United Future as an Independent MP with a fringe party attached.