The statement comes just weeks before the Gulf Arab state hosts the 2022 men's FIFA World Cup, Reuters reports.

HRW said it had interviewed six LGBT Qataris, including four transgender women, one bisexual woman and one gay man, who said they had been detained between 2019 and 2022.

They said they had been kept without charge in an underground prison in Doha and subjected to verbal and physical abuse, including kicking and punching.

One individual said they were held for two months in solitary confinement.

"All six said that police forced them to sign pledges indicating that they would 'cease immoral activity'," HRW said.

The group added that transgender women detainees were forced to attend conversion therapy sessions at a Government-sponsored clinic.

One of the transgender Qatari women interviewed by HRW told Reuters she was arrested several times, most recently this summer when she was held for several weeks.

Authorities had stopped her due to her appearance or for possessing make-up, the woman said, adding that she had been beaten to the point of bleeding and had her head shaved.

The behaviour centre she was mandated to attend told the woman she had a gender identity disorder and accused her of being transgender in search of "sympathy from others".

"The last thing I want is sympathy, I just want to be myself," she said.

A Qatari official said in a statement that HRW's allegations "contain information that is categorically and unequivocally false".

He added: "Qatar does not tolerate discrimination against anyone, and our policies and procedures are underpinned by a commitment to human rights for all.

"The Qatari government does not operate or license any 'conversion centres'.

"The rehabilitation clinic mentioned in the report supports individuals suffering from behavioural conditions such as substance dependence, eating disorders and mood disorders, and operates in accordance with the highest international medical standards."

Homosexuality is illegal in the conservative Muslim country, and some footballers have raised concerns over the rights of fans travelling to the event.

Organisers of the World Cup, which starts on November 20 and is the first to be held in a Middle Eastern nation, say that everyone, no matter their sexual orientation or background, is welcome, while also warning against public displays of affection.