ACT has not only held onto the 10-fold increase in voter support it enjoyed last election, it's maintained a stable caucus and gained further traction.

ACT's leader David Seymour (centre-right) is known to many New Zealanders; his MPs like Karen Chhour, Brooke van Velden and Nicole McKee (left-to-right) less so.

ACT has not only held onto the 10-fold increase in voter support it enjoyed last election, it's maintained a stable caucus and gained further traction.

With polls anticipating an even bigger stable of MPs after October, the minor party is lining up for a potentially major say in the shape of the next government.

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The results have also trended towards the National Party being able to form a government solely with libertarian ACT's support, meaning not just more MPs, but seats in Cabinet, i.e. coveted ministerial positions.

The mid-July 1News-Verian poll projected 46 seats for National and 15 for ACT, just reaching the 61-seat threshold for being able to form a majority government. Newshub-Reid at the end of last month had National and ACT with one further seat each. Most recently though, the Taxpayers Union-Curia poll had National with 44 seats and ACT on 17 - an even bigger proportion for the smaller party.

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However, that last poll also had New Zealand First returning to Parliament, and while National and ACT could form a government on those numbers, the margin is incredibly slim. ACT has also ruled out working with NZ First, which has been appealing to a similar voting base.

National has been careful to avoid alienating either party, and exactly how that shakes out will be a question that remains unanswered until after the election.

What seems clear is ACT is on track for expansion and a bigger role in decision-making than ever before.

Leader David Seymour has become a familiar face in New Zealand politics, but the other candidates aren't so well known.

Who are they? And what do they want to achieve in Parliament? …

Go to this episode on rnz.co.nz for more details