Russel Norman has been key in the Green Party gaining credibility, says former Whanganui candidate John Milnes.
Dr Norman yesterday announced he would step down as the party's co-leader in May. He has been at the helm for nine years and will remain an MP.
Mr Milnes, who has run for the Whanganui seat at three elections and two under Dr Norman's leadership, said the party co-leader had improved markedly as a political leader in his first few years and since then had been instrumental in growing the party's vote.
"I've been really pleased with him as leader," Mr Milnes said.
"Certainly there was an appreciation of his abilities with economics. It wasn't one of our strong points in our early days and it was one of the criticisms of us, but he was able to explain the importance of economics and its connection with the environment.
"I think he was credible to those who were otherwise sceptical."
Mr Milnes said the timing of Dr Norman's resignation was right, giving a new leader three years to settle before the next election.
He said there were several within the party who could step up as leader.
Kevin Hague and new MP James Shaw were two he pointed to.