JIMMY Kimmel has taken aim at disgraced Hollywood mogul Harvey Weinstein in his biting Oscars opening monologue.

Kimmel discussed the Academy taking action to expel Weinstein from their ranks in the wake of rape and sexual harassment allegations.

"There were a lot of great nominees but Harvey deserved it the most," Kimmel said, to applause.

He joked if Hollywood leads by example and wipe out harassment in the workplace, "women will only have to deal with harassment every other place they go".

Kimmel spoke of the #MeToo and Time’s Up movements as being "positive change" and joked that he remembered a time when studios didn’t believe women or black people could open a movie.

“The Academy as you are no doubt aware took action last year to expel Harvey Weinstein from their ranks,” Kimmel said.

“What happened with Harvey, what's happening all over was long overdue. We can't let bad behaviour slide anymore, the world is watching us, we need to set an example.

“The truth is, if we are successful here, if we can work together to stop sexual harassment in the workplace. If we can do that, women will only have to deal with harassment all the time at every other place they go.”

Meantime, Kimmel also hilariously addressed last year’s Best Picture envelope fiasco in his opening monologue at the Oscars.

"This year, when you hear your name called, don’t get up right away -- give us a minute," Kimmel joked onstage at the Dolby Theatre.

The Oscars host said he was asked last year if he wanted to do comedy with the accountants: "The accountants went ahead and did comedy on their own. But it won’t happen again."

Of course, he was referring to last year’s debacle when La La Land was wrongly announced by Warren Beatty and Faye Dunaway as the winner of Best Picture, when the actual winner was Moonlight in an epic stuff up.