One of the behind the scenes battles in this year's election campaign is that of New Zealand First vs Greens.

The battle is mainly for relevance. Both are vying to be the party that most helps determine the outcome of an election that is very much about National vs Labour.

As the third largest party, the Greens are trying to achieve this by getting Labour 'over the line'. New Zealand First is attempting to be the 'king maker' between National and Labour.

The fortunes and decisions of these two parties will be crucial over the next six months as both parties could play a central role in determining who will govern after 20 September.

The Focus on New Zealand First

Winston Peters is the 'man of the moment' - with significant media attention focusing on the centrality of his party, and speculating on which parties he might work with. Peters is not the only politician being tricky about post-election coalitions, but his obfuscation is certainly the most striking and relevant, as I pointed out in my column last week - see: Six months for voters to demand coalition transparency.

In the weekend, Peters continued to respond to and deflect questions about what he would do with any 'king making' powers he has after 20 September. You can watch his 15-minute interview with Patrick Gower on The Nation: Winston Peters: Asset buy-back 'a priority'. This interview is summed up well in Tony Field's 2-minute TV3 report NZ First's future coalition deal unknown. For a review of Gower's interview, see Paul Casserly' Into the void. He concludes, 'As a TV spectacle these encounters with Peters are unequalled, like the joy one gets from watching someone attempting to wrestle a greasy pig. It's going to be an interesting ride to the election thanks to planet Winston'.

Torben Akel also has a very good 7-minute report asking How will kingmaker Winston Peters act this election?.

Who will Peters choose? And what are NZ First's bottom lines?

Speculation continues about whether Peters is more likely to go into coalition with National or Labour. There are many good arguments for both prospects. But there are increasing signs that Peters might smartly position his party to operate on the 'cross benches', where arguably he may have much more power. By essentially holding a minority government to ransom, a party on the cross benches could have major influence over legislation on a day-by-day basis.

This is something Matthew Hooton has argued could happen: 'Mr Peters' greatest driver is to be at the centre of events. The best way for him to achieve that in 2014 is to stay outside the government, offering no one confidence and supply. That would enable Mr Key's government to limp on but without Mr Peters having to take responsibility for its decisions. Even more attractive, whenever he was so inclined, he could engage on an issue, putting himself on centre stage. To pass a Budget, the government would either have to negotiate with him for months in advance or - more likely - have to present it to Parliament with no surety of passage. Dramatic concessions could then be demanded in exchange for NZ First's votes. No doubt it would all end in tears but it would be a rollicking three years. Mr Peters would love it. He could then retire to the north, go fishing and have a good laugh with his mates' - see: What would Winston want?.

That cross benches scenario is anathema to Mike Hosking: 'Let's just be clear - if Peters ever did hold the balance of power outside government, you would have in display the perfect example of all that is wrong with MMP. A small party holding all the power. A small party with all care and no responsibility. You would have tradeoffs and blackmail all over the place. Not even your most ardent MMP supporter could argue that's fair and reasonable' - see: Campaigning on the tail wagging the dog.

For more coverage of what Peters has declared to be his key coalition negotiating issues, see the Herald's Peters: Limit foreign ownership of property and Charlie Gates' Peters backing fix for 'icon'.

For some examination of exactly what Peters might 'really mean' and what he might 'really do', see Pete George's NZ First bottom lines and Frank Macskasy's Winston Peters recycles pledge to "buy back state assets" - where have we heard that before?.

Also, today on Radio NZ's Nine-to-Noon, Matthew Hooton and Mike Williams discussed the positioning by Winston Peters as well Green Party issues - listen here: Politics with Mike Williams and Matthew Hooton.

Labour moving away from the Greens in favour of NZ First

With the relevance of New Zealand First apparently increasing, it appears as if the Greens are correspondingly decreasing in relevance. This is partly due to the Greens faring poorly in recent opinion polls, but also because they appear to have no leverage over Labour to ensure they are included in any potential Labour-led Government after 20 September.

Labour now appears to be tilting more towards NZ First, and away from the Greens. Rodney Hide discusses this in his column about last week's battle between Shane Jones and Gareth Hughes - see: Bold No3 grabs the spotlight. The key part is this: 'The Jones approach is to knock the Greens about and win votes for Labour. It's not like the Greens can take umbrage and shift their support to National. And without options the Greens face the danger of being again stood up. Helen Clark chose Winston Peters over the Greens in 2005. It's a tough choice: Winston or the Greens. But that may well be the choice Labour again confronts. In the meantime, there is a compelling electoral logic for Labour putting a distance between themselves and the Greens'.

For Chris Trotter's view, see: Five Easy Pieces: How the Greens can stop Labour playing silly-buggers. He calls for the Greens to play hardball with Labour.

Co-leader Russel Norman appeared on TVNZ's Q+A programme yesterday, and Corin Dann pushed this line - that the Greens are being marginalised by Labour - for which Norman had no real comeback - see the 8-minute interview: Greens target housing and power prices.

Are the Greens becoming beige?

Some of the Greens' decline probably relates to the party's rather colourless political nature lately. In its very strong attempt to be a serious and conventional political institution, the Greens appear to have foregone some of the party's original colour and uniqueness. In the Q+A interview, for example, Russel Norman came across blandly and focused mostly on middle-of-the-road messages about 'responsible fiscal policy', 'paying off debt' and being 'fiscally prudent'. Similarly, in the weekend, business reporter Richard Meadows interviewed the co-leader about personal finances, and received some notably bland and conventional responses - see: Frugal Russel true to his roots.

Of course, if the Greens eventually want to prosper electorally, and gain more leverage for future coalition negotiations, it might well be smart for the co-leaders to take such a conservative approach for the party, and focus on winning votes from the centre and right of the political spectrum. A new blog has some very interesting and heavily analytical posts arguing exactly that - see Fundamentally Useless' Looks like it's up to you, Green Party, Which Blue votes can the Greens steal? and How to take several thousand Blue-Green votes from the Right.

Green progress and success

Many recent policy announcements from the Greens have reiterated the more moderate approach this year and the party is reaping some rewards for this. Most recently, the party's focus has been on environmental issues that resonate with more middle-class voters. For instance, see Isaac Davison's Greens tell kids to cycle to school. This received positive feedback from not just the Herald - see: Greens' school transport idea makes sense - but even from David Farrar - see: A Green policy with some merit. Sean Plunket saw both merit and negatives in the policy - see: Let kids make their way.

So far this year, the major policy announcement from the Greens has been its solar energy programme for housing. This received some positive coverage - see, for example, the Herald's editorial Green power worthy but has too few incentives and No Right Turn's A sensible policy. But as some noted, the new solar-focus represents a strong shift towards harvesting the middle class vote - see Martyn Bradbury's A brief word on the Greens tilt towards the middle classes with solar scheme.

The Greens have come out with another interesting policy on politician pay, saying that MP annual pay rises should be in line with the average New Zealand employee. Such a policy is carefully crafted to resonate with those concerned about economic inequality, while rather conservatively not actually challenging MPs remaining amongst the top 1% of income earners. On this policy, however, the Herald was less enthusiastic - see: Greens' pay push makes little sense.

Also in the policy area of political finance, the Greens have announced a policy of reforming political donation laws - see Neil Reid's Greens seek to ban corporate. This will have strong appeal, but the populist policy has many fishhooks and it avoids the fact that there are much bigger sources of money for the parties - such as donations from wealthy individuals (generally the owners of the companies that would be banned from donating), as well as the money from backdoor parliamentary resources.

What the new Green Party list means

Today the Greens have announced their initial party list for the 20 September election - see Isaac Davison's Genter, Shaw big winners in Greens draft list. According to Rob Salmond, some of 'those big moves show a desire by the Greens' central team to present a list more palatable to business than in the past' - see: The Greens' draft list. Genter and Shaw are both from the more environmentally-focused, non-left side of the party - what might be called the New Greens faction - people who are more at home in the business world wearing corporate attire than amongst the far left. The rise of James Shaw is particularly important, and for an older profile of the politician, see Claire Browning's Meet James Shaw, Wellington Central Green candidate. There will be many that see Shaw as a future co-leader of the party.

Despite the Greens current poor polling, the party always campaigns well in election year. This time, digital campaigning will be particularly important for the party. For the latest analysis of what the Green MPs are doing on Twitter, see Matthew Beveridge's blog posts, MPs on Twitter: Mojo Mathers, MPs on Twitter: Gareth Hughes, and Something that was brought to my attention.

Finally, to see how Labour really views the Greens, see Scott Yorke's satirical blog post, A statement from Shane Jones.