"I honestly think that that's mythologising. Clearly there are some people who are unhappy with some of those decisions, and as with any political party there are also philosophical differences around political direction.
"We've always had debate, it's a political party."
He acknowledged there was always a risk of a small support party being overshadowed by its bigger partners but the Greens had been aware of that risk going into government.
"We do have a very, very strong long-standing brand and a very core and clear set of values and a very strong core group of supporters who will get us through. But we have to deliver on the confidence and supply agreement."
Ten months into the parliamentary term, some former Green MPs say the current caucus is in danger of becoming invisible.
Catherine Delahunty, who was a Green MP for nine years, said they were facing a predictably hard struggle.
"It was always going to be really, really tough going in terms of making sure the wins were clearly attributed to them and they were incredibly visible," she said.
"People really need a reason to want to be there and it's really important they are not perceived as 'Labour Lite'. In order to do that the Greens need to be brave and I think that's a really key discussion that I know the party will be having and should be having at this time."
Sue Bradford, who quit the party when she left Parliament in 2009, said she believed the Greens were blowing a great opportunity to build the party and push their agenda forward.
She said the party was becoming "less and less the party of choice for people on the ecological and social justice side of the Greens".
And former MP David Clendon, who is attending the conference as a delegate, said there was a popular perception the party was very much playing second fiddle to New Zealand First.
But fellow former Greens MP Nandor Tanczos said the Greens had achieved some important victories.
"It's not just about what they've agreed; it's about the relationship they have and whether they can work constructively with good faith, and I get the sense that that is true."
The Greens have negotiated some wins, such as consultation on the Zero Carbon Bill, a $100 million Green Investment Fund, the establishment of a Climate Change Commission and a ban on single-use plastic bags.
"Being a small party in coalition is a very difficult position and we've seen so many small parties crash and burn in that position," Tanczos said.