Police raided the Wellington home of investigative journalist Nicky Hager for 10 hours last Thursday as part of its investigation into his source for the Dirty Politics book.

Nicky Hager Source: Associated Press

Blogger Cameron Slater laid a complaint with police over the theft of his emails - the emails which were used to write the book.

Mr Hager says five police arrived at his home with a warrant and took computers, drivers, phones, CDs, a camera, an Ipod and other papers belonging to himself and his family.

He says he did not have any documentation relating to the Dirty Politics book in his home.

He was not home at the time.

"I am confident the police took nothing that will help them with their investigation. Their actions were a fishing expedition, presumably because they have no idea who the source is and hoped they might stumble across information about them," Mr Hager said late this afternoon in a statement.

Mr Hager told ONE News he was in talks with lawyers.

He's described the actions as "dangerous" for journalism.