The vandals who graffitied the makeshift memorial at the site comedian Eurydice Dixon was raped and murdered have been called cowards by Victoria Police, hours ahead of a planned vigil.
Offensive markings were found about 3.50am painted on the North Carlton sporting field where flowers and tributes have amassed since the shock attack on the 22-year-old last week.
"You're not a brave man if you assault a woman, you're not a strong man if you assault a woman, you're not a smart man if you assault a woman," Assistant Commissioner Stephen Leane told reporters on Monday.
And "if you engage in that sort of graffiti", you're none of those things either, he added.
Items have been seized from the scene and the dog squad went through the area, with the investigation ongoing.
Fire crews used high-pressure hoses to remove the paint.
Mr Leane, Chief Commissioner Graham Ashton, Police Minister Lisa Neville and Melbourne Lord Mayor Sally Capp met on Monday to discuss safety measures for the city and Monday's vigil.
Police will be at Princes Park during the event, but have been told to take a step back and allow people to grieve.
Ms Neville said more CCTV cameras were being installed in the city as part of an anti-terror safety package.
While she insisted Melbourne was safe, she acknowledged events such as this were a shocking reminder of vulnerabilities.
"You get incredibly affected by it, and particularly women, because this is the starkest of the things that you worry about," she told reporters.
Police over the next month will do a community safety assessment of Princes Park and Melbourne's Town Hall will be lit in Orange on Monday night, the colour of the international campaign to end violence against women.
Vigil organiser Megan Bridger-Darling told the Nine Network Monday's graffiti was "absolutely galling, and insulting and deeply, deeply offensive".
The nation's political leaders used Question Time on Monday as a call-to-arms against violence to women.
"This is a heartbreaking tragedy. But what we must do as we grieve is ensure that we change the hearts of men to respect women," Prime Minister Malcolm Turnbull said.
"We start with the youngest men, the little boys, our sons and grandsons, and make sure that they respect their mothers and sisters and all the women in their lives."
Opposition Leader Bill Shorten said as a Melburnian, Ms Dixon's death had an added layer of dread.
"All of this violence is ultimately preventable and we need to tackle the enablers of violence and change the attitudes of men," he said.
Thousands of people are due to hold vigils across the country in tribute to Ms Dixon, five days after she was raped and killed on her way home from a comedy show at the Highlander Bar in the CBD on Tuesday night.
"We all should be able to walk home, whenever we want, wherever we want, and assume we will make it home safe," the organisers of Monday night's Reclaim Princes Park vigil posted on Facebook.
Last week Broadmeadows 19-year-old Jaymes Todd appeared in Melbourne Magistrates' Court charged with Ms Dixon's rape and murder.