In the 2017 poll, National saw its 2104 vote tally eroded by only one percent, despite attempting to win a fourth term and facing a much revitalised Labour Party.
National did best in Auckland City and within Auckland, excelled in those electorates, like Botany, which receive the largest number of immigrants.
As a country we issue huge volumes of residence visas - more per capita than almost any other OECD country.
This doesn't happen by chance.
The Cabinet sets a target, euphemistically called a "planning range" for the number of residence approvals to be granted each year.
The most recent planning range authorised by the National Party Cabinet was 42,500 residence approvals per year.
This amounts to a city bigger than Gisborne every year.
Between 2014 and this year nearly 150,000 residence visas were approved, with the great majority of these immigrants settling in Auckland.
This human flood has put enormous stress on Auckland's infrastructure and services and cost all of us plenty as taxpayers.
Schools are jam-packed, our hospitals can't cope and the pressure on accommodation has seen house prices spiralling upwards to the point where home ownership, for most young people is an improbable dream.
We are now reaching a situation where essential workers who are paid at levels set nationally like teachers, nurses and police, simply cannot afford to make Auckland their home.
Hawke's Bay-born demographer Professor Paul Spoonley says: "The numbers coming in are huge. We're taking almost twice the number of immigrants Australia is, and we're taking three times the number of immigrants that the UK is."
In addition, New Zealand has very liberal rules around voting and virtually all of these migrants granted residence automatically gain the right to vote. Most similar countries require migrants to go a step further and gain full citizenship before voting is permitted.
A young Australian journalist I met during the election campaign was staggered to find that she had a vote in our election when the Kiwi boyfriend who she'd accompanied to Auckland would be unlikely to ever get a vote in Australia where he'd lived for years.
Five years ago I bought an Auckland house at a real estate auction in a large room packed with Asian faces. That the great majority of these punters were recent Chinese recent immigrants was attested by the presence of Mandarin/English translators.
The political affiliation of this element of the flood of new "Kiwis" is well researched.
Studies I saw a decade or more ago, but which are still likely to be valid, showed that the bulk of these new New Zealanders have generally conservative attitudes, disapprove of our social welfare net and don't much like tax of any kind.
A New Zealand Herald survey published recently concluded "National would easily be able to govern alone without the need of any support parties if Chinese voters in New Zealand had their way, a new poll has found. The WTV-Trace Research Chinese Poll found 71.1 per cent of ethnic Chinese will vote for National if the election was held tomorrow."
A study, backed by local Chinese media company World TV found Chinese voter turnout in the 2014 General Elections was 78.5 per cent - higher than the national average of 76.8 per cent.
So what we have is the National Government consciously setting extremely high "planning ranges" for new residents which results in the importation of large numbers of reliable National Party voters.
It seems hard to believe that given the negative impacts of this torrent of humanity that any government would allow this situation to run on as long as it has, but for the fact that there is a clear political advantage to the National Party in doing so.
New Zealand First has long campaigned on heavily reduced migrant intakes and it would be fascinating to be a fly on the wall when the immigration "planning range" comes up at coalition negotiations.
Mike Williams grew up in Hawke's Bay. He is CEO of the NZ Howard League and a former Labour Party president. All opinions are his and not those of Hawke's Bay Today.
