In terms of the future of New Zealand's economy, Clay said it was important that "the huge amounts of money being spent at the moment" are invested "wisely, in building a sustainable future".
"We are already doing that here in Whanganui with the redevelopment of the port, and the city has really come alive in the last two or three years.
"The port is an access point, it's sustainable and it brings jobs, so these are the sorts of things that we need to be focusing on in the next few years.
"There's no point in putting it into roads and tunnels like [National] are planning, because that's wasted, it's a backward-looking investment and it's not going to generate a return."
Clay said he had spent a "lifetime in the arts" but had always maintained a keen interest in politics.
"I've been interested in politics all my life and I actually studied politics at university back in the day, as well as running for election as an 18-year-old for the Labour Party in East Coast Bays.
"There has been a lot of community arts stuff all around the world, I've written five books and four film scripts, two of which have been produced into award-winning movies.
"I've just retired, so it's a lifetime of work really, and a hugely enjoyable one at that."
Clay said his mother, Dame Marie Clay, was one of the first people to be named New Zealander of the Year for her work in education, after beginning her career as a teacher at Castlecliff Primary School.
"She became professor of education at Auckland University and went on to become one of the most respected educationalists in the country.
"We have a world-leading education system here in New Zealand, that's my perspective from my mother's work.
"The Greens are really passionate about that public education system, because we really believe in it."
Clay said Whanganui's agriculture industry also needed to move in a more sustainable direction.
"There is a big movement of sustainable farming now, and those people are leading the way, because we need to take the long-term view, as opposed to chasing a quick gain," he said.
"There is always that tribal thing that goes on, but I think people are more open to the ideas of other parties at the moment, and I that's a product of the time we're in."