"In New Zealand with our clean, green image, our isolation, I think we're a sitter for being proactive in that area."
He was won over by Labour leader Jacinda Ardern's statement at the Labour Party campaign launch that climate change was "my generation's nuclear-free moment".
"When we went nuclear-free it wasn't easy, there was some pain associated with it. But you wouldn't find any New Zealanders now you would turn around and say it wasn't the right thing to do."
Hubbard has donated $15,000 to Labour this year, as he has in previous election years. But he did not plan to throw any more of his financial heft behind the party.
"We don't have deep, deep pockets. We did it on the basis that Labour always has trouble attracting the donations that the National Party and Act do."
Hubbard was elected as Auckland's Mayor in 2004 but only lasted one term before being ousted by John Banks. While he stood as an independent, he was backed by left-leaning parties.
Labour has promised to make New Zealand carbon-neutral by 2050, to bring all sectors into the Emissions Trading Scheme including farmers, and to lock emissions reduction targets into law.