Adam Lambert's raunchy performance at the American Music Awards, which included him kissing a male keyboard player, has led to a flood of complaints to US broadcasting organisations.

ABC was taken by surprise when one of the former reality TV star's dancers stuck his face in the singer's crotch during the performance in New York of For Your Entertainment - a moment that was cut out when the awards show was broadcast on a tape-delayed basis on the US West Coast on Sunday.

During a rehearsal the openly gay former American Idol contestant thrust a male dancer's face toward his crotch, though the dancer did not get as close to Lambert in the rehearsal as he did on Sunday night.

At one point during rehearsals, Adam also caressed a male dancer's upside-down face, but he kept his hands off the dancer's cheeks on Sunday night.

"A lot of what I do is kind of freestyle," the singer said about the routine's choreography.

"That's how it was on Idol. That's how I perform. I like to have a framework, and just do stuff. So that kind of came about because of the connection that I had with that dancer."

Both hostile and supportive comments were posted online about the glam rocker's performance.

While prowling an elaborate set during the number, Adam also fondled one dancer and briefly led two dancers around on a leash. It followed the song's lyrical theme in which the singer warned: "It's about to get rough for you."