Speaking this morning on Newstalk ZB, Mr Key acknowledged arguments made in recent days by the RSA, which is hoping the current flag stays in existence.
"You see the arguments from the RSA that, well, people fought and died under the flag -- and that's true. They certainly did fight under the flag.
"But I think they actually fight for values and principles -- human rights, women's rights and democracies."
Mr Key pointed out that many Commonwealth war tombstones featured a silver fern.
"That's the national symbol of New Zealand -- that's what we're known by.
"The reason why I support the change of a flag is simply because we will wear it, use it and promote it more. It's therefore all about national pride and recognition of our country and showing the world how great we think New Zealand is.
"And I don't think we do that very much with our current flag."
