Key Points:

An injunction covering outgoing National Party leader Don Brash's missing emails has been lifted.

A National Party spokesman confirmed Dr Brash's lawyer had filed the application at the High Court at Wellington this morning and the injunction had been lifted.

The interim injunction, issued by the High Court at Wellington last Thursday, restrained anybody from putting Dr Brash's emails on a website, broadcasting them, handing them to someone else or revealing their contents.

It also required anyone with the emails to hand them over to the court.

The step - rare in New Zealand - came after he was dogged for months by rumours that potentially damaging emails to and from him would be made public.

Dr Brash said he sought the order because he did not want his private correspondence broadcast to the world.

He said he also wanted to protect people who had corresponded with him in confidence.

The injunction prevented investigative journalist Nicky Hager from publishing his book The Hollow Men: A Study in the Politics of Deception.

Mr Hager said the book was an inside look at the National Party under Dr Brash's leadership and was based not only on emails to and from Dr Brash, but other internal correspondence and interviews with unhappy party members.

"I believe the injunction is aimed at suppressing unwanted news and the motivation of senior National Party people is to try and avoid accountability for their actions," he said.