In his first visit to Melbourne since the Victorian election campaign officially started, Prime Minister Scott Morrison has paid his respects to the victim of a deadly terror attack, insisting he was not on the hustings.

But after visiting Pellegrini's, the espresso bar co-owned by Sisto Malaspina, who was killed on Friday, Mr Morrison stood beside Victorian Liberal leader Matthew Guy and championed his credentials as a future premier.

"It's what Victoria needs and not just on issues of law and order, but on the issues of cost of living equally, he's been stepping up," Mr Morrison told reporters.

"He's got a vision for Victoria as a lifelong Melburnian, the heart and soul of Melbourne beats in him as well and I think would beat passionately in a government that he would lead."

Mr Guy said he visited Pellegrini's two weeks ago with colleagues and thanked police for their quick response to Friday's attack.

"Enough is enough for our city, we will not accept, whether it's terrorism or violent crime, that this is going to be the norm for a city of five million-plus people," he told reporters.

"There is no greater challenge and there is no greater responsibility for government to keep the population safe and that is what Melburnians expect and that is what they should be receiving."

Mr Morrison's visit was brief and he has now left Australia for Singapore and the East Asia Summit.

His help on the campaign trail had been flagged by Mr Guy on Friday, hours before Hassan Khalif Shire Ali set alight a ute laden with gas cylinders on Melbourne's Bourke Street and launched a stabbing frenzy on pedestrians, killing Mr Malaspina.

Coalition partner, the Nationals, later promised a $1 billion decentralisation fund if they form government with the Liberal party after the November 24 poll.

Premier Daniel Andrews on Tuesday promised $32 million for public IVF services for low-income couples struggling to get pregnant.

"Everybody should be able to get everything they need in order to have the joy of children, the magic that is a family," he told reporters.

But both major parties piled on the Greens over revelations the minor party's candidate for Footscray, Angus McAlpine, once fronted a hip hop group that released songs with depraved lyrics revelling in date raping and domestic violence.

It's the second time during the campaign that leader Samantha Ratnam has had to face scrutiny over a candidate, after upper house hopeful Joanna Nilson last month withdrew over social media posts.

But Ms Ratnam stood by Mr McAlpine. He will continue as a candidate and is "deeply sorry ... for the offence, the degradation, the humiliation and the triggering that those lyrics that I once performed have had on anyone who's heard them".

He said he moved overseas in 2012, aged 23, to escape a culture of "toxic masculinity and cheap crude humour of a hiphop culture" and is now "ashamed" of the lyrics.

The Greens say they are working on their vetting processes to earlier weed out candidate problems.