Mana Party candidate and former Green Party member Sue Bradford says the Greens "dobbing in their own members - goes against all principles of activist solidarity".
In a live chat with nzherald.co.nz readers today, Mrs Bradford described Mana as a "party for the future".
"We face the economic and environmental crises with realism, and know we've got to build for a future in which everyone has a chance to live a decent life at the same time as protecting and nurturing the physical world around us."
Mrs Bradford said National's biggest failure is a lack of understanding how the New Zealand "economy really works or any vision of how we could all work together to make a fairer, happier society".
"This country and the rest of the world are still in a recession caused by dodgy bankers who speculated against the best interests of most people.
John Key was right at the heart of this sort of dealing and is the last person we should be putting in charge of our economic, social and environmental wellbeing. Our problems will be overcome by working together, not by relying on the greedy types National represents, who got us into this situation in the first place."
Mrs Bradford left the Greens in 2009, as the party had moved further to the centre of the political spectrum.
"The Greens are definitely not a spent political force - they are simply moving into a part of the political spectrum occupied by most other Green Parties around the world - ie an environmentally focused, socially liberal middle class party which is comfortable with greening capitalism and with supporting whichever major party of right or left they are able to cut the best deal with at the time. The Greens are winning blue green votes because of this - it's a very deliberate strategy."
While Mrs Bradford said the Greens have abandoned their activist roots, political activism is still thriving in New Zealand.
"The days of 'true activism' are certainly not dead - there are plenty of us, younger and older people who are committed to working for social, economic and environmental change through action in our communities, workplaces and on the streets. I am just sorry that the Greens no longer treasure their activist heritage - doesn't mean there aren't still plenty of us out here."
Mrs Bradford was scathing of the Green co-leader Russel Norman's decision to name those responsible to placing political slogans on National Party billboards.
"I don't think that placing intelligent, easily removable stickers on billboards is a serious crime - it's part of election campaigning. The worse offence from my point of view is the Green Party leadership dobbing in their own members - goes against all principles of activist solidarity."
Asked what she thought if Mana Party billboards had been defaced, she said it would depend on how they had been vandalised.
"If they were really defaced or destroyed I wouldn't be happy about it - but that's not what happened on Sunday night - it was simply a matter of removable stickers being placed on a small part of the billboard, no damage done," she said.
"As long as it's tastefully done and makes political sense - it's all part of election campaigning - would rather have pointed political comment than silly moustaches or wholesale deconstruction of my billboards."
Green Party co-leader Metiria Turei this morning dismissed the criticism from Mrs Bradford that activists could not trust the party not to dob them in.
"It's absolutely critical for the Green Party that we continue to run a clean campaign," she told Radio New Zealand. "We have been the subject of dirty tricks - so was Sue in her time as a Green MP - we've been the subject of dirty tricks to try to undermine us and we don't play those dirty tricks."
"It's important for members to know that."
Ms Turei said the party had always been ethical in its campaigning, and did not expect the issue to hinder the party's campaign.
"I think it is very important to be clear that the Green Party was not responsible for that vandalism.
She said the party had been open and honest with the public and displayed "real leadership".
"We can't be held responsible for everything a member does.
"We have told the public everything we know and taken action as best we can."
Ms Turei said members had told her they were "deeply disappointed" with the vandalism.
"Our membership overall is committed to a clean campaign and clean politics and I support them 100 percent."
- HERALD ONLINE