'Lovable rogue' Mick Gatto sues integrity champion

Underworld identity Mick Gatto is suing an anti-corruption champion, claiming he was portrayed as a murderer who sat atop the devastating Melbourne gangland wars.

The defamation lawsuit centres on an interview on Nine Network's 60 Minutes program about the CFMEU.

Geoffrey Watson SC discussed his CFMEU-focused report entitled Rotting from the Top in which he alleged Mr Gatto controlled M Group labour hire companies through "dummy directors" and received special treatment from the union and lucrative returns.

Mr Gatto sought to file an amended statement of claim for reputational damage in the NSW Supreme Court on Tuesday.

Lawyer Barry Dean alleged imputations in the 60 Minutes interview that his client was implicated in murders during Melbourne's gangland wars, and in one imputation committed a murder himself.

Mr Dean quoted Mr Watson saying he was "a little bit sick and tired, and this includes members of the press, treating Mick Gatto like he's some lovable rogue", and that had to stop.

"Mr Gatto was sitting right at the top of those gangland wars which devastated Victoria for around a decade," Mr Watson was quoted as saying.

The integrity champion's reference to Mr Gatto's past conduct was a bid to prove he was not a "lovable rogue", Mr Dean said,

"The ordinary, reasonable visitor to this interview ... would understand that Mr Watson was making an accusation that my client was responsible for those killings," he said.

Mr Watson's imputation was that Mr Gatto was "a murderous member of the mafia".

The 60 Minutes program was primarily about Mr Gatto's business practices and his conduct in the building industry, the court was told.

But Mr Dean said the "defamatory effect" of the past murder and building industry corruption imputations was substantially the same.

"It's never been the case that you can prove bad reputation by newspaper articles," he said.

Justice Campbell noted the corruption allegations involved Mr Gatto manufacturing industrial disputes in order to then settle them and get paid for it.