DUA Lipa says she has been left in tears after fans were reportedly forcibly removed from her concert in Shanghai.

The English-Albanian pop singer took to Instagram in solidarity with concertgoers, saying she was "horrified by what happened" during her show on Wednesday night in the city's Qingpu district.

Fans voiced outrage on social media as they shared videos of security workers forcibly ejecting people from the gig during Dua Lipa's first tour of China.

Some said people were pulled from their seats by security for standing up and dancing during the performance while others said it was because they were waving pro-gay rights flags.

One woman said she saw an incident between several security personnel, the police and a Chinese couple. The man was held in a headlock before he was removed, she said.

She described the police as "heavy-handed" and "aggressive".

Homosexuality is not illegal in China, although anti-LGBT attitudes do exist and some have said there is a recent trend to sideline the LGBT community, the BBC reports.

Noticing the commotion while on stage, the One Kiss singer appeared noticeably upset. She told the crowd: "I want us all to dance, I want us all to sing, I want us all to just have a really good time.

"I would love in these last few songs for us to really, really, really enjoy ourselves. How about that?"

She later posted a message to fans on Instagram, praising concertgoers for their bravery.

"I am proud and grateful that you felt safe enough to show your pride at my show," Dua Lipa wrote.

"What you did takes a lot of bravery. I always want my music to bring strength, hope and unity. I was horrified by what happened and I send love to all my fans involved.

"I would love to come back for my fans when the time is right and hopefully see a room full of rainbows."