OPINION: In the tiny Waikato village of Matangi, a century-old factory stands as a lasting relic of New Zealand's fledging dairy industry.

Cream from the factory was churned into the earliest Anchor butter. It was the first to produce Highlander condensed milk

The creamery was built by Glaxo, producing milk powder, and grew to become the largest dairy factory in the world. The company eventually amalgamated into GlaxoSmithKline, a pharmaceutical giant.

When it closed in 1987, the sprawl of old buildings would have been left to rot away. But the site was bought, and restored by Hamilton entrepreneur Harry Mowbray.

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Harry Mowbray and son Tom at the Matangi Dairy Factory.

Mowbray now has a new project: protecting New Zealand's primary industries from the scourge of climate change policies.

He's the driving force behind the Heartland Party, a new vehicle struggling to get off the ground before September's election.

Mowbray wouldn't talk to me for this column. Nor would Jock Allison, an agricultural scientist, who is linked to Heartland.

But here's what I understand.

The party would position itself as a party representing rural interests, and as a likely support partner to National.

Six to eight candidates would run in countryside electorates, but ask supporters to give their party vote to National.

BRITTANY PICKETT/STUFF Former Invermay director and agriculture scientist Jock Allison.

The desire is to exploit a particular feature of MMP and create an "overhang".

This tactic has previously benefited the Māori Party (in 2005, 2008 and 2011). It happens if a party has more electorate MPs than proportional seats.

The party vote determines what proportion of the 120 seats in Parliament a party gets when they are divided up according to the election results.

If there is an overhang, it increases the size of Parliament, and means a higher majority is needed for any party to form a Government.

Heartland are looking to hold the balance of power. But they are yet to approach National about a deal.

They have monumental hurdles to clear. Fundraising isn't a concern: the primary industries are generous givers to political causes that support their interests: just ask Winston Peters. But they must find and sign up 500 members in only a few short months.

Seeding a crop of new candidates into blue constituencies is also a big ask. Even if National MPs agreed to swap the kudos and privilege of a safe seat for a high list ranking, there is very little time to raise the profile of Heartland.

Then there is credibility. Their policy platform is predominantly anti-environment.

They want the Emissions Trading Scheme (ETS) and the current Government's freshwater reforms abandoned.

ROBERT KITCHIN/STUFF The Heartland Party would like to support Simon Bridges' National Party.

None of this is helpful to National, or the sector, which is currently trying to convince the world they are responsible and cautious guardians of the planet.

It's no secret many farmers are alarmed by current Government policies. But is it enough for them to put their faith in an untested party? Probably not.

The current system favours incumbents. And single issue parties rarely fare well - the Greens survived because they broadened their policy base.

Our political landscape is littered with the gasping corpses of micro-parties who tried to get going in election year: Colin Craig's Conservative Party, Kim Dotcom's Internet Party. (In a neat quirk, Mowbray's three children now own the former Dotcom mansion).

Heartland's ambitious ideas seem destined to spoil.