Labour Party MP and shadow Attorney-General David Parker is calling on the Police to further investigate claims made in Nicky Hager's book Dirty Politics.

He has used Parliamentary Privilege to name Mark Hotchin as a man alleged to have paid Cameron Slater and PR man Carrick Graham to run a smear campaign against the Serious Fraud Office while he was being investigated over his finance company Hanover Finance.

While he won't repeat the claims outside Parliament, David Parker told Newstalk ZB's Mike Hosking police need to look into how far Mr Slater took the attacks.

"We know that thousands of dollars were being paid to Cameron Slater - Whaleoil - and Carrick Graham, and that they were busy trying to undermine the Serious Fraud Office. What we don't know is whether that crossed the line."