Auckland Mayor Len Brown is not commenting on claims Cameron Slater asked an ex-prostitute friend to dig up more dirt when his affair was exposed.
Nicky Hager's book Dirty Politics contains a chapter on the mayoral sex scandal, which the author calls Slater's "most spectacular operation to date and also the grubbiest".
He claimed Slater was trying to get a right-wing mayor for the Super City by means of a sex scandal, publishing details of an affair between Brown and council adviser Bevan Chuang on his Whaleoil blog on October 15.
When it became clear Mr Brown would not resign, Hager said Slater approached an ex-prostitute friend to dig up more stories.
On October 23: "Rattle your cages to see if Len rooted in brothels". On November 18: "Did Brown use Mustangs [gentleman's club]?".