Homeless people are being chased away from airconditioned centres and harassed by ''cranky passers-by'' as they attempt to seek refuge from the extreme heat.
The city's rough sleepers say it is too hot to sleep at night. During the day, they are often moved on from cool public places, including shopping centres, fast-food outlets and public toilets, according to support workers.
One man who has been sleeping at Fitzroy Gardens said the heat brought out what he described as ''weekend warriors''.
Youth Projects' Melanie Raymond said clients tell her ''people turn narky when it's really hot and they lash out''.
Drug safety outreach worker James Morgan said security guards would move people along because they looked homeless or drug-affected.
''There's a lot of occasions that we'll come across a client that is completely zonked out in the sun and they are red raw.''
Fairfax Media asked the operators of several airconditioned public places in Melbourne about their homelessness policies. A Melbourne Central spokeswoman said the issue was not relevant to the venue because only its stores were airconditioned.
The State Library of Victoria has an extensive list of bylaws, including that a person not ''wilfully disturb, annoy, offend, or obstruct any other person in the proper use of the library''.
''Otherwise, we certainly encourage people from all walks of life to come and enjoy this public space,'' a library spokeswoman said.
On Thursday morning Melbourne City Council announced they would provide the city's homeless with free access to their pools.
"They need to go to the Drill Hall or to the Salvos who can sort them out with a voucher as well as towels or bathers if they need," a spokeswoman said.
Ms Raymond said there should be an official hot weather plan for Melbourne's homeless that would be triggered by extreme temperatures.
There's a lot of occasions that we'll come across a client that is completely zonked out in the sun and they are red raw.
Youth Projects' day drop-in centre offers free water, sunscreen and basic aid to rough sleepers. But its free medical clinic on Hosier Lane is already down to its last bottle of sunscreen.
The centre stays open up to five hours later on extreme heat days, but receives no extra funding from the Victorian government. ''So we're doing more with less,'' Ms Raymond said.
Rough sleeper Kieran said during the hot weather it became harder to maintain his sense of pride. ''Sorry to be gross about it but it's not like you can jump in the shower and change your undies.
''If I'm really on the nose people want to keep away from me. It does very little for my self-respect … and that's pretty much all I have on the streets.''