An American soprano has spoken of her hurt and anger over “cruel” verbal abuse and harassment from opera critics whom she accused of body-shaming.

Kathryn Lewek’s performance as Eurydice in a raunchy production of Jacques Offenbach’s Orpheus in the Underworld at the Salzburg festival has been widely praised.

But some writers also reviewed her body shape, describing her as “buxom” and “stocky”. One wrote about the production’s director, Barrie Kosky, making overweight women in tight corsets spread their legs.

Lewek said her role in the production was clearly a sexualised one and her costumes included a black corset. “It’s not like I wasn’t expecting some people to comment on my body,” she said.

“I’m heavier now than I ever have been in my life because I had a baby 10 months ago and I decided to breastfeed her for at least a year. It’s not like I live under a rock, I know that opera is both an audio and a visual experience but I was just really surprised at the body-shaming.

“I was really surprised several reviews used the word ‘buxom’. You know, it can be construed as a compliment I guess, but OK, don’t describe me with the same kind of words that you would describe a porn star. It’s weird and why are we commenting on women’s bodies anyway?”

Lewek posted details of her experience on Twitter and was overwhelmed by the support she received, she said, but she was also shocked by the “horror stories” she heard from fellow professionals.

HELP! Please help me spread the word. Opera singers are often the targets of #harassment, #bodyshaming & #fatshaming from #operacritics. This must stop. #timesup on on these juvenile bullies. Please share and join the discussion. Spread the word! #shameoncritics /thread pic.twitter.com/iJhvsS7jfY — KATHRYN LEWEK (@KathrynLewek) August 26, 2019

“This is not a new fight but I feel like we are living in a slightly different atmosphere, so I felt it was an opportunity to call attention to this,” she said. “It is not OK. My colleagues deserve better than this. This is my first brush with this kind of verbal harassment and it has really opened my eyes.”

On Twitter, Lewek described how she returned to the stage as Queen of the Night in the Metropolitan Opera’s production of The Magic Flute six weeks after giving birth to her daughter.

“Dozens of airports and pitstops have hosted my nursing sessions, and I’ve also pumped breast milk into bottles in a myriad of odd places, such as dressing room shower stalls, restaurant bathrooms, parking lots and in dressing rooms during wig and makeup changes.”

She said she knew there were cruel people in the world, “but before this past week it had not dawned on me that such crass and petty cruelty could be found amongst the supposedly highly educated and cultured people that we trust to discuss and critique art in its highest form”.

Lewek took particular offence at an article by the music and dance critic of the German newspaper Die Welt, Manuel Brug, who wrote about overweight women in corsets spreading their legs. Brug said the article was not a review but a report about a binge-watching weekend in Salzburg. He said the point he was trying to get across was one about Kosky repeatedly putting women in “unsuitable” costumes.

“If she is so sensitive, why is she showing herself the whole time in this corset?” he said. “It is interesting that the thin ladies on stage all had dresses and the not so thin ones have costumes where you see a lot of her weight.”

• This article was amended on 29 August 2019. An earlier version stated that there was a world tour of the Metropolitan Opera’s production of The Magic Flute. This was not the case.