Key Points:

National leader John Key has revealed he would like to take the tourism portfolio if he becomes Prime Minister, arguing that it offers big economic opportunities and is all about branding the country.

Mr Key made the comments on TV One's Agenda programme yesterday when he was pushed to say what portfolio he would want.

"It's no great secret, my interest would be to consider taking the tourism portfolio," Mr Key said.

"That's my thought process at this point, and the reason for that is I think it's a massive industry for New Zealand, where we can do an awful lot better."

Prime Minister Helen Clark holds the arts, culture and heritage portfolio along with her responsibilities at the helm of the Labour-led Government.

Former Labour Prime Minister David Lange held the education portfolio, while Sir Robert Muldoon was Finance Minister while also being Prime Minister.

Mr Key said tourism was potentially New Zealand's largest export earner.

National's current spokesman on tourism is long-serving MP Lindsay Tisch.