The Prime Minister wants the silver fern on the flag to make New Zealand more marketable to the world.

Legislation allowing two referenda on the matter is currently before Parliament

John Key says if we change the flag, and it becomes the Silver Fern, inevitably you will see companies use it far more prolifically than they do today.

"There's a reason why Air New Zealand put the silver fern on their planes. They're not stupid, they know that that's not New Zealand in the eyes of international consumers."

But marketing expert James Bickford argues changing the flag should not be a branding exercise.

He believes a flag represents a country's heritage and its purpose and values, and a money value should not be put on it.

"I don't think you can suddenly take my personal understanding of a flag, change it and try and turn it into a brand."