Chris Isaak's roadies lambasted the handful of women who worked on the singer's tour, calling one a bitch and a c**t, and hurling shocking homophobic slurs at a male roadie ... this according to allegations in a new lawsuit.

Lane Hirsch -- who worked on Chris' tour for 17 years as a lighting designer and technician -- claims in his suit ... he was fired after repeatedly complaining to Isaak and others that the 2 female roadies were treated horribly and he was on the receiving end of crude anti-gay comments.

Hirsch says after he complained that one of the roadies was abusive, a number of his colleagues went after him with a vengeance, calling him a "f*g" and a "little girl." He claims crew members would say, "blow me," and "suck my d**k you little f*g."

Hirsch also complained of choking on marijuana smoke but no one took him seriously.

According to the lawsuit, Isaak -- who is a defendant along with others on his crew -- knew full well what was going on but did nothing.

Hirsch says he was unceremoniously fired without notice. He's suing for wrongful termination, defamation and discrimination.