Prime Minister John Key has hit back at critics of New Zealand's "100 per cent pure" brand and says we shouldn't let the rest of the world "talk us down".

Britain's Daily Mail labelled New Zealand "100 per cent manure" in the wake of the Fonterra crisis, and Chinese media have labelled the Tourism New Zealand slogan a "festering sore".

However, Mr Key said people should take the criticism with a grain of salt.

"They are often people who have an agenda of their own that they want to push. One of them happens to be a British taboid who, with the greatest of respect, probably doesn't like us doing the haka when we have All Black test matches as well."

As Minister of Tourism he knew visitors rated the environment highly on their holidays here.

"100 per cent pure is a marketing campaign, it's the envy of tourism organisations around the world and just because the Daily Mail doesn't like it we won't be changing [it]."