A SYDNEY council has been shamed after asking a gay and lesbian support service  which provides professional development for the NSW Police  to remove its promotional banners from a community festival.

Parramatta Council has been accused of homophobia after Lord Mayor John Chedid allegedly instructed an advisor to ask Twenty10 to remove two promotional banners at the Rediscover the River Festival at Parramatta last week.

The banner read: "Support service for gay, lesbian, bisexual, transgender, same-sex attracted and gender diverse young people, their families and community. 'A place to be me, with the support I need.' www.twenty10.org."

Twenty10 acting managing director Terence Humphreys said the stall at the festival had been well received but that they were so offended by the incident that they packed up and left.

"Without this signage, Twenty10 would not have been visible to those who needed us most or even to the general public to know what we do," Mr Humphreys said.

"Our signage simply describes our work and who we work with."

Mr Humphreys says he wants an apology from the Lord Mayor.

"We've heard from a number of sources that the Lord Mayor was personally offended by the banner," he said.

"(Being) personally offended is (the mayor's) right but they don't have the right to use their power to further marginalise people who are already marginalised such as young people of diverse genders and sexualities."

Since the incident on Thursday, about 6300 people have since signed a fast-moving petition on Change.org calling on Mayor Chedid to apologise to the not-for-profit organisation, which Parramatta Council had invited to participate in the festival.

The council released a statement today after hundreds of angry comments were posted on its Facebook page.

"In response to numerous complaints made by members of the public, organisers of the Rediscover the River event asked Twenty10 to remove two promotional banners," the statement said.

"At no stage did the Lord Mayor or council staff ask Twenty10 to quit their participation at the event.

"Council regrets any inconvenience or offence taken by its actions and values the efforts, and contribution of Twenty10 in servicing at-risk youth.

"Council has enjoyed a positive relationship with Twenty10 over some time and hopes to continue to work in partnership over the coming years."

Mr Humphreys said the office of the Lord Mayor was yet to respond to Twenty10 directly, despite him sending a "firmly worded" email to both his office and the office of Sydney's Lord Mayor Clover Moore.

"In the email I also specifically explained what was wrong with his request and that it was in fact a breach of the anti-discrimination legislation," he said.

"I also requested that the Lord Mayor's office apologise to the people of Twenty10 and to ensure us they will undertake some professional development in anti-discrimination and sensitivity around these issues."

Mr Humphries said he expected a response in coming days.

"We've been assured by the council that the Lord Mayor (of Parramatta) will respond to my email but I haven't received anything as yet," he said.

"The CEO of the City of Parramatta said he'd spoken to the Lord Mayor and assured me it wouldn't happen again but that's actually not enough.

"The Facebook post by Parramatta City Council … does not constitute an acceptable response from the office of the Lord Mayor."

He said the instruction to remove the banners was "truly offensive".

"For the office of the Lord Mayor to display such homophobia and transphobia is appalling," he said.

"If we don't receive an appropriate or sufficient response we'll most definitely take this further, potentially to the anti-discrimination board."

News.com.au has requested an interview with Lord Mayor John Chedid and is yet to receive a response.