Columnist Julie Burchill should be sacked for her "disgusting rant" against transsexuals, a coalition minister said on Sunday.
Liberal Democrat Lynne Featherstone condemned an Observer piece in which the journalist made a series of cutting comments about "bedwetters in bad wigs" and "shemales".
The article was penned in defence of Burchill's fellow writer, Suzanne Moore, who came under fire on Twitter after suggesting that women were expected to look like "a Brazilian transsexual".
Burchill wrote that "screaming mimis" had accused her friend of "white feminist privilege" and forced her to leave the social networking site.
Transsexual, Roz Kaveney, wrote a Guardian blog in reply on Sunday.
She wrote: "It's hard to know where to begin with Burchill's defence of Moore – with 'Black and White Minstrel Show', 'bed-wetting', or her odd assumption that all trans people are middle-class and overeducated."
"What I would ask Moore and Burchill is this: do you think that what you've written makes it more or less likely that an elderly trans woman living on a housing estate will get jostled on the stairs by her neighbours?
"Or that a teen trans man will be punched in the street? It's not anger-fuelled tweets, but that provocation, done with malice by people who should know better, that is the real bullying."
A note from the Observer readers' editor, Stephen Pritchard, was later added to the article on the newspaper website.
"As you might imagine, I have received many emails protesting about this piece this morning," the note said. "Thank you to those who have written. I will be looking at this issue and will be replying to all in due course."
Posting on Twitter last night, Featherstone - a former equalities minister currently at the Department for International Development - wrote: "Julie Birchill (sic) rant against transgender community is absolutely disgusting - a bigoted vomit for which the Observer should sack her."
A Guardian News & Media spokeswoman said: "We acknowledge the strong reaction to Julie Burchill's piece published in The Observer.
"As indicated by Observer editor John Mulholland on Twitter, we are taking such reactions extremely seriously and we have asked our independent readers' editor to urgently investigate the matter."