NEW YORK: Gay rights campaigners on Wednesday hailed a watershed speech by the United Nations chief Antonio Guterres in support of the "LGBTI community", but said words must be followed by action.

In the first ever address by the head of the United Nations to the UN LGBTI Core Group - which was established in 2008 to oversee gay rights globally - Guterres said the multinational body would boost efforts to end anti-LGBT+ abuse and violence.

Concerns are rising about a possible rollback of hard-won LGBT+ rights worldwide - from a U.S. partial ban on transgender individuals serving in the military to a recent first punishment of a Russian minor under a law against so-called gay propaganda.

Amir Ashour, executive director of Iraqi gay rights group IraQueer, said the U.N. secretary general's comments "normalise LGBT+ rights and acknowledge them as a part of human rights".

However, he warned that words alone would have little impact in countries such as his home country of Iraq where the LGBT+ community faced verbal and physical threats on a daily basis.

"The secretary general and the U.N. need to constantly ... and actively work on encouraging them to change policies," he told the Thomson Reuters Foundation by email.

Currently, 70-odd countries worldwide still criminalise same-sex relationships. Earlier this month, India's top court scrapped a colonial-era ban on gay sex in a landmark judgment.

Guterres made his statement on the 70th anniversary of the Universal Declaration of Human Rights, which enshrined human rights at the core of the United Nations' ethos and work.

"Many ... (LGBTI community) members are imprisoned, abused and even killed simply for who they are or whom they love," he said on the sidelines of the annual meeting of world leaders.

"But so long as people face criminalisation, bias and violence based on their sexual orientation, gender identity or sex characteristics, we must redouble our efforts to end these violations."

Maria Sjödin, deputy executive director of global campaign group OutRight Action International, said it was important to build on the work of former U.N. chiefs to boost LGBT+ rights.

"It's great, as we've been waiting to get something longer and more substantial than just a response to a couple of questions that he's had before," she said.

"It's really important not to backslide and to ensure that the human rights of LGBTI people continue to be a priority for the U.N. and the secretary general."

Also speaking at the event highlighting anti-LGBT+ violence, newly appointed U.N. High Commissioner for Human Rights, Michelle Bachelet, said "profound, positive change is possible".

"More than 70 countries criminalise consensual same-sex relationships, and also criminalise transgender people based on their appearance," she added."

"These laws subject LGBT people to long prison sentences, and in some cases physical punishment. They also implicitly encourage prejudice, hatred and violence. But laws can change."