A book about the war in Afghanistan which was banned by American authorities reveals details of the activities of New Zealand intelligence teams there, it was reported last night.

TV One News said the Pentagon bought and destroyed nearly 10,000 copies of Lieutenant-Colonel Anthony Shaffer's book Operation Dark Heart, and only 200 survived.

The report said One News had obtained copies of some pages from the original version of the book, which is now available in censored form.

The pages revealed how New Zealand's intelligence operatives worked with their American counterparts in Afghanistan.

Green Party MP Keith Locke, a persistent critic of New Zealand's involvement in Afghanistan, said the book raised the question about the extent to which New Zealanders were still part of joint operations.

"The book indicates our intelligence people are part of US teams that are pin-pointing the location of people for assassination, often by drone aircraft."

Defence Minister Wayne Mapp said accounts in the book were at least six years old.

"I'm not going to talk ... about the operations the special forces have undertaken, but I can assure New Zealanders that our special forces operate absolutely strictly by the law."

New Zealand has a Special Air Service unit in Afghanistan.