Claire Trevett: Shane Jones, wisteria and the Maori seats pickle

The wisteria was this big. NZ First candidate Shane Jones. PHOTO/Michael Cunningham

NZ First candidate Shane Jones has always been fond of a colourful analogy, but the rigours of doorknocking in Whangarei are clearly taking their toll.

Asked this week about NZ First's policy for a referendum on the Maori seats, he started banging on about wisteria.

"I've learnt to my cost that Maori politics can be like a clambering plant - like a wisteria. It can pop up in all sorts of places."

Asked what the hell he was talking about, he apparently recalled he was now in NZ First and changed his creeper of choice to a Chinese jasmine - "creepy crawly bloody plants, you don't know where they're going to end up."

Jones was being asked about the issue because he is himself on the Maori roll and has previously advocated keeping the Maori seats until Maori themselves say they are ready to let them go. That was NZ First's policy when he joined the party and when he agreed to be a candidate.

A mere few weeks later with no input from or warning to Jones, NZ First leader Winston Peters announced that policy had now changed and he would push for a referendum on the future of the Maori seats.

Peters decided the best approach to get people to look his way was to prod awake the hibernating bears of smacking and the Maori seats.

Peters is also trying out some CPR on that old bug bear 'separatism' which has not worked on a mass scale since Don Brash in 2005. Thus far, his efforts on that count have only attracted the attentions of that very same Brash, who has effectively endorsed Peters and even considered a donation - an association that appalled some NZ First stalwarts and which even Peters pretended he had not heard about.

Peters based his call to get rid of the seats on the 'fact' that Maori were deserting the seats in their droves and a majority of Maori were on the general roll.

Far be it from me to question the Master of Facts, but both these 'facts' were fictions.

The Electoral Commission statistics show that in 1997, 2001 and 2006 more than double the number of Maori switched from the general roll to the Maori roll than vice versa.

At the last Maori Electoral Option in 2013 it was almost even - but the net impact was still an extra 7,052 on the Maori roll and the vast majority of new Maori voters opted for the Maori roll over the general roll.

Since National shelved its Maori seats policy as a condition of its governing agreement with the Maori Party in 2008, there has been little attention paid to the matter.

The reason attention is being paid to it this time round is because there is a prospect of it happening.

Admittedly, by ramping up his stance on the matter Peters is at risk of the bear he has woken turning on him.

NZ First still gets a lot of support in the Maori seats. It has not stood candidates in them since 2001 but in 2014 it still got about 11 per cent of the party vote there - higher than the nine per cent it got nationwide.

But Peters' decision to boost his policy to a referendum could be taken as a promising signal from National that Peters is at least preparing some policies he knows only National would agree to in post-election negotiations.

When he was leader in 2002 English also advocated getting rid of the seats. It was former Prime Minister John Key who shelved it, deciding it was not worth the fight.

But English is more ideological than Key and should it be on the table after the election, National would like nothing more than to be able to point to Peters as the man who killed the Maori seats rather than cop the blame itself.

The general belief is that a binding referendum on the matter would effectively sound the death knell for the seats. Although NZ First MP Pita Paraone rather optimistically suggested there was a lot of support among non-Maori for the seats on social media, relying on Twitter for salvation is a flawed strategy.

Jones managed to toe the party line just in time. But he might want to take care when explaining himself to northern Maori: the pruning advice for wisteria recommends "removing suckers from the bottom."