Interactive: 'Jacinda effect' and poll turnout helps Labour

Analysis of the election results shows while the right bloc of parties was still slightly ahead of the left after the 2017 election, the left had all but closed the gap.

The results showed a six percentage point swing toward the parties on the left (the Greens and Labour) and a 6.5 percentage point swing away from those on the right (National and Act) compared to 2014.

Parties in the centre which were not aligned to one side or the other remained more or less static - and one of those, NZ First, was left as the kingmaker.

• Explore the results in our Herald Insights interactive

The analysis of the swing comes as the parties have argued over whether the election result was a clear sign of a desire for change or a vote of confidence in National's record and handling of the government.

There is no clear answer - although there was a massive upswing for Labour under leader Jacinda Ardern - and an increase in turnout which favoured the left - the right was still marginally ahead showing there was still confidence in National.

The right parties (National, Act and Conservative) got 1,171,403 votes between them, about 72,400 fewer than in 2014. Of those, 1.15 million were National voters. The drop was courtesy of the near disappearance of the Conservative Party, which had secured 95,600 votes in 2017. All but 6,200 of those found a new home in 2017.

The margins between the left and right blocs is even smaller in terms of the parties returned to Parliament, 1.165m voters supported the right bloc of National and Act (up 17000) while 1.118m supported the left bloc of Labour and the Greens. The gap is a mere 46,500 voters.

NZ First was the only centrist party to return with 186,700 votes.

National's result alone was more than the 1.12 million who voted for left bloc of parties (Labour, Greens, Internet and Mana) - but those parties got 226,780 more than in 2014.

The centre or unaligned parties of NZ First, TOP and the Maori Party were up 40,400 votes between them although that increase was solely due to TOP's 63,261 vote result as both NZ First and the Maori Party lost votes - and neither TOP nor the Maori Party made it into Parliament.

While National's vote went up by 20,574 it commanded a lower share of the overall vote and was down 2.6 points. Labour's rocketed up by 351,649 votes - a whopping 12 percentage point increase.

That appeared to include most of the 95,000 voters the Green Party had lost since 2014 - it was down 4.4 points. NZ First also suffered but was less hard hit - down by 21,600 votes and 1.5 points.

The mix included about 194,800 voters who had not voted in 2014.

Labour's vote went up in every electorate. It picked up the most extra votes in Nelson (7910), Port Hills (7311), Wellington Central (7194) , Selwyn (6854) and Dunedin North and South (about 6660 in each). It picked up more than 3000 votes in every electorate bar four, all of which were seats in which Labour already polled well - New Lynn, Mangere, Manurewa and Manukau East.

National lost votes in 26 electorates, but gained in the rest. It took its hardest hits in Wellington Central and the Christchurch and Dunedin seats, as well as provincial towns such as New Plymouth.

It held up in Auckland - and gained votes in many farming and rural areas, although its share of the vote dropped in some. Its biggest gain was in the Canterbury electorate of Selwyn (up 3194) although that was countered by Labour's larger gain and resulted in a 4.5 point drop in National's share of the vote. It also gained 3076 in Hunua, 2959 in Rodney, and 2293 in Waikato.

It gained in its share of the vote in only nine electorates - many of them strong Labour seats in which National increased from a small base such as Manukau East where National went up 2.7 points - but only got 805 more votes than in 2014.

It dropped in Epsom by 1029 votes - a five point drop - while Labour went up 11 points and 4530 votes.

Epsom is a safe National seat where National voters support Act's David Seymour to keep Seymour in Parliament as a possible support partner for National.

The seats in which National lost most votes were Wellington Central (down 1533 votes, a drop of 7 percentage points), New Plymouth (down 1452 votes, a seven point drop), and Labour leader Jacinda Ardern's Mt Albert electorate (down 1247, a five point drop).

It was also hit by a swing in Labour's favour in Canterbury, where National had claimed most of the seats in the aftermath of the earthquake. That included Christchurch Central (down 1345, a 5.6 point drop), Ilam (1243, down five points), and Port Hills (down 1338, a six point drop).