"A lot of what I said in 1972 seems really simplistic and naive in retrospect - talking about zero population growth, zero economic growth, technology control."
But he believed history had proved most of their environmental concerns right: "There's also the whiff about it, looking back, of backing the right horse, of getting on board modernity's biggest bandwagon when it was just the size of a skateboard," Mr Brunt said.
The party captured 5.3 per cent of the vote in its first general election in 1972, but gained no seats under the First Past the Post system.
Despite being at the heart of the anti-nuclear movement, homosexual law reform and the campaign for MMP, it never made it into the Beehive, and folded in the late 1980s.
The party lived on in the Green Party.
The Greens' charter was based on Values' manifesto and the party was led into Parliament by former Values members Jeanette Fitzsimons and the late Rod Donald in 1999.
Forty years on, Values members hope to educate young voters about the Green Party's roots at the reunion.
Ms Browning said it was important that Greens did not lose sight of the Values manifesto and become "the more human and environmentally friendly face of Labour". Values and Greens' treatment of the economy as an ecological issue, not a growth issue, was what set them apart from other political parties.
"Greens campaigned [in 2011] on an economic platform ... and it presented the party as being much more like everyone else, much more conventional."
The author was heartened by speeches from co-leaders Russel Norman and Metiria Turei since the 2011 general election, which reaffirmed that the original values of social justice and inclusion were at the heart of their policy.
In his first speech after the election in December, Dr Norman spoke about how he identified with the Christmas story and the importance of "love and compassion towards each other", living "with truth and justice between one another" and with "awe and respect for the natural world".
Ms Fitzsimons said the issues of social justice and sustainability were pushed into the political background in the 1980s by Prime Minister Robert Muldoon's economic reforms.
Asked whether she felt this could happen again, and whether Greens could splinter like the Values Party, she said: "No. The signs that we were right are all around us."
Claire Browning, Beyond Today: a values story, self-published, $15. Email values.story@gmail.com for a copy.