Former Lord Mayor of Melbourne Robert Doyle has been the victim of a "political witch-hunt" and has been denied the "presumption of innocence" amid sexual harassment claims, former Victorian premier Jeff Kennett has said.

In a statement released by his lawyer, Mr Doyle announced his resignation on Sunday, seven weeks after an investigation was launched into allegations of sexual harassment and indecent assault.

Mr Doyle has strenuously denied the allegations.

Mr Kennett today launched a defence of Mr Doyle, who he said he has known for 40 years.

"Robert Doyle is not a predator," he said.

"He is a very likable individual."

"I think there has been very much a political witch-hunt both within the council and within the State Government."

The City of Melbourne appointed Dr Ian Freckleton QC to investigate after sexual harassment and indecent assault claims were made by former councillor and one-time factional ally Tessa Sullivan.

The investigation was later broadened after Greens councillor Cathy Oke also alleged she had been sexually harassed.

In January, Victorian Health Minister Jill Hennessy asked her department to investigate Mr Doyle, who was chairman of the Melbourne Health, after a third woman made claims of sexual harassment.

Mr Kennett said he did not know whether Mr Doyle had crossed the line, but said the investigation and media reporting had been one-sided and flawed.

"This is getting so easy to make accusations," he said.

"It always takes two to tango.

"Some of the claims are very light, in real terms. There's been no… misuse of office in trying to secure favours, as has occurred overseas, where this started.

"There's been no sexual attacks in terms of the more serious forms of sexual activity. It's about a hand on the knee, a kiss, a pat on the back and the more substantial claim by the ex-councillor."

Freelance journalist and documentary-maker Louise Pascale told ABC Radio Melbourne that Mr Doyle was a public figure and the media had a right to report the allegations.

"It is going to be in the media, it's unavoidable, I don't know whether it's a trial by media, as everyone is saying, but it's actually the reporting of the news," she said.

"People that have events happen in their lives that are reported in the news all go through this in varying levels and it does impact on their mental health and it does impact on their well-being."

She said it was not easy for women to come forward with accusations, particularly as the scrutiny is often on the victim and what they were wearing and what they were doing.

"Let's not forget these women, it's not easy to do what they're doing, and they're not doing it for any other reason than to take their course of justice, which they believe they have a right to," she said.

Robert Doyle 'had enormous power'

Mr Doyle has not given an interview to the media since the council investigation was launched but he hired public relations firm.

Former Councillor Stephen Mayne was critical of Mr Doyle's approach to responding to allegations against him.

"He's running a PR campaign with a PR company through favoured media outlets," he said.

Mr Mayne gave evidence to Dr Freckleton, after he said he saw Mr Doyle inappropriately touch Cr Oke during a job interview process.

Mr Mayne claims it was towards the end of the evening after plenty of wine was consumed.

"[Robert Doyle] had enormous power, and he abused that power," Mr Mayne said.

"We really need to seize the moment, and learn the cultural lessons. We need a new female lord mayor, we need more support for the victims, we need more female voices in the media," he said.

In response to Mr Mayne's comments Mr Doyle's lawyers said "[Mr Doyle] is presently hospitalised and receiving treatment for serious mental and physical conditions.

"Due to [Mr Doyle's] condition he cannot readily defend himself."

Cr Doyle was first elected to the lord mayoralty in 2008.

He was Victoria's Liberal Party leader between 2002–2006.