Icelandic icon Bjork, who has built one of the boldest careers in pop music, has lashed out at the media for its "sexist" views, saying women are expected to sing about romance, not science.

"Women in music are allowed to be singer-songwriters, singing about their boyfriends," she wrote in an impassioned Facebook post late Wednesday. 

But, she added, "if they change the subject matter to atoms, galaxies, activism, nerdy math beat editing, or anything else (other) than being performers singing about their loved ones, they get criticised."

Bjork said she hadn't "moaned about sexism" through most of her career, but got fired up after criticism of her DJ set at a Texas festival last weekend.

"Some media could not get their head around that I was not 'performing' and 'hiding' behind desks. And my male counterparts not. And I think this is sexism," she wrote.

The 51-year-old musician, a former leader of The Sugarcubes post-punk group, was wearing a mask while DJing at the Texas gig as she has in other performances.

Despite four decades in music, and including a starring role in Lars Von Trier's award-winning film "Dancer In The Dark", Bjork said she was only accepted by critics last year with the release of an autobiographical album about her break-up from longtime partner, the artist Matthew Barney.

"I made 'Volta' and 'Biophilia' conscious of the fact that these were not subjects females usually write about.... I sang about pregnant suicide bombers and for the independence of (the) Faroe Islands and Greenland... I sang about galaxies and atoms but it wasn't until 'Vulnicura', where I shared a heartbreak, I got full acceptance from the media," she complained on Facebook.

"If we don't cut our chest open and bleed about the men and children in our lives, we are cheating our audience."

The singer of "Venus As A Boy" and "Human Behaviour" has previously criticised the media over its coverage of the music industry. In June she was quoted by NME slamming music journalism as "a boys' club. They like music that is... well, a lot of it is for boys."

Bjork, who in March announced she was working on a new album, wrote this week that in 2017 she would "get to have a costume change" and abandon the subject of heartbreak in lieu of new inspiration.