The United Nations Special Rapporteur on the Right to Housing, Leilani Farha, said a plan to outlaw people camping in the city and fine those who leave their personal items unattended was a serious international human rights concern.

"The criminalisation of homelessness is deeply concerning and violates international human rights law," Ms Farha said via a statement from the Office of the United Nations High Commissioner for Human Rights in Geneva.

"The proposed law goes further and is discriminatory - stopping people from engaging in life-sustaining activities, and penalising them because they are poor and have no place to live."

Ms Farha has contacted the Australian federal government's Attorney-General's Department about her concerns.

The statement follows a chorus of criticism from local law and homelessness experts, which has so far failed to deter City of Melbourne officials from pressing ahead with the changes.

The City of Melbourne has insisted its reforms do not "ban" homelessness.

But Homeless Law manager and principal lawyer Lucy Adams said the changes could effectively ban rough sleeping by preventing homeless people from sleeping on the streets with swags or blankets.

Ms Adam said it was "quite concerning and embarrassing" for Melbourne that the actions of the council had attracted international attention.

"We should be doing better than this," she said.

"The eyes of the world are watching our next step".

City of Melbourne chief executive Martin Cutter said the council received a letter from the UN Special Rapporteur on March 3, and on Tuesday sent a reply via the Attorney-General's Department "explaining that council is not banning homelessness".

"It is not illegal to be homeless and council is working hard to reduce homelessness in the City of Melbourne," Mr Cutter said.

He said Victoria Police Chief Commissioner Graham Ashton had asked the council to consider changing its local laws in response to large homeless camps around the central city.

In January Mr Ashton described these camps as "disgusting" and a "very ugly sight".

It's understood that Ms Farha, a lawyer and executive director of Canada without Poverty, was made aware of the proposed bylaw changes through media coverage.

The press release with her comments was issued under the headline "Proposed 'Homeless Ban' in Australia cause for concern - UN Expert" alongside releases about human rights in North Korea and fears over a chemical disaster in eastern Ukraine.

Ms Farha said under human rights law, the social exclusion of people that were homeless was strictly prohibited.

"The local council now has an opportunity to reverse its course at the next vote and reconsider the proposed changes," she said.

"I encourage the city to focus on its human rights obligations, which leave no room for discrimination."

Former Commissioner for Children and Young People Bernie Geary has been appointed by the council to oversee weekly meetings with homelessness services and authorities.

Mr Geary said the advice of the United Nations Special Rapporteur should be taken seriously.

"I think we should be listening to people like her, because we don't want to be criminalising homelessness. We don't want to be moving down that track and I don't think the City of Melbourne is either," he said.

"From what I can gather it seems to me they are desperately trying to seek solutions."

The City of Melbourne is taking submissions about its proposed law changes until Thursday.

It has already received more than 1300 responses, including 98 surveys completed by homeless people.

Fairfax Media sources said most of the submissions opposed the camping ban, although the council and Melbourne lord mayor Robert Doyle also regularly receive demands from ratepayers and visitors to "clean-up" the city's homeless camps.

The proposed changes to local law would broaden the definition of camping, so that any type of camping would be banned. Those found illegally camping could face a $250 infringement fine, or a court fine of up to $2000.

Homeless people could also be fined $250 for leaving items unattended, and would have to pay to have their items returned.

The council has already approved an education campaign to deter people from donating goods directly to the homeless people.

Fairfax Media has approached the United Nations for further comment.

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