Bill English says it comes down to Māori to preserve Te Reo.

"The language will be saved by the people who own it and love speaking it," the National Party leader told The AM Show on Tuesday.

"Māori need to speak Māori if they want to preserve the language."

A controversial new book, Killing Te Reo Māori, claims everything we're doing to save the language is having the reverse effect.

Mr English says a statistic mentioned in the book, stating one in five Māori under the age of 30 speak Te Reo, is "probably higher" than expected.

"It's promising.

"I think it's doing a bit better... I don't think it actually is failing, if anything it's probably holding.

"The Government has some obligations through the treaty. It's met them in my view. We've spent a lot of money on TV, on resources for schools and so on.

"Probably a bit more can be done with resources for schools and teachers, but in the end it needs people who want to speak it."

"But the owners of it need to speak it and that is people in their households.

"You can't rely on a Government and a bureaucracy to save someone else's language."

Mr English says it is still recognised as a huge part of New Zealand's identity.

Newshub.